21095649 has 9 divisors (see below), whose sum is σ = 30491409. Its totient is φ = 14054580.

The previous prime is 21095629. The next prime is 21095653. The reversal of 21095649 is 94659012.

The square root of 21095649 is 4593.

It is a perfect power (a square), and thus also a powerful number.

21095649 is a `hidden beast` number, since 2 + 1 + 0 + 9 + 5 + 649 = 666.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 21095649 - 2⁵ = 21095617 is a prime.

It is a super-3 number, since 3×21095649³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21095609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 13014 + ... + 14544.

Almost surely, 2^21095649 is an apocalyptic number.

21095649 is the 4593-rd square number.

21095649 is the 2297-th centered octagonal number.

It is an amenable number.

21095649 is a deficient number, since it is larger than the sum of its proper divisors (9395760).

21095649 is an frugal number, since it uses more digits than its factorization.

21095649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3068 (or 1534 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The cubic root of 21095649 is about 276.3106536761.

Multiplying 21095649 by its sum of digits (36), we get a square (759443364 = 27558²).

It can be divided in two parts, 210 and 95649, that added together give a palindrome (95859).

The spelling of 21095649 in words is "twenty-one million, ninety-five thousand, six hundred forty-nine".