21095684 has 6 divisors (see below), whose sum is σ = 36917454. Its totient is φ = 10547840.

The previous prime is 21095677. The next prime is 21095693. The reversal of 21095684 is 48659012.

It can be written as a sum of positive squares in only one way, i.e., 20502784 + 592900 = 4528^2 + 770^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2636957 + ... + 2636964.

It is an arithmetic number, because the mean of its divisors is an integer number (6152909).

Almost surely, 2^21095684 is an apocalyptic number.

It is an amenable number.

21095684 is a deficient number, since it is larger than the sum of its proper divisors (15821770).

21095684 is a wasteful number, since it uses less digits than its factorization.

21095684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5273925 (or 5273923 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 21095684 is about 4593.0038101443. The cubic root of 21095684 is about 276.3108064859.

Subtracting from 21095684 its sum of digits (35), we obtain a square (21095649 = 4593²).

The spelling of 21095684 in words is "twenty-one million, ninety-five thousand, six hundred eighty-four".