21150801 has 45 divisors (see below), whose sum is σ = 37264491. Its totient is φ = 11920608.

The previous prime is 21150757. The next prime is 21150803. The reversal of 21150801 is 10805112.

The square root of 21150801 is 4599.

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

It can be written as a sum of positive squares in only one way, i.e., 12006225 + 9144576 = 3465^2 + 3024^2 .

It is not a de Polignac number, because 21150801 - 2⁷ = 21150673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21150803) 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 44 ways as a sum of consecutive naturals, for example, 289701 + ... + 289773.

Almost surely, 2^21150801 is an apocalyptic number.

21150801 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21150801 is the 4599-th square number.

21150801 is the 2300-th centered octagonal number.

It is an amenable number.

21150801 is a deficient number, since it is larger than the sum of its proper divisors (16113690).

21150801 is an frugal number, since it uses more digits than its factorization.

21150801 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 83 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 18.

The cubic root of 21150801 is about 276.5512376339.

Adding to 21150801 its reverse (10805112), we get a palindrome (31955913).

The spelling of 21150801 in words is "twenty-one million, one hundred fifty thousand, eight hundred one".