21957698 has 16 divisors (see below), whose sum is σ = 38940480. Its totient is φ = 9085776.

The previous prime is 21957697. The next prime is 21957707. The reversal of 21957698 is 89675912.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21957697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26636 + ... + 27447.

It is an arithmetic number, because the mean of its divisors is an integer number (2433780).

Almost surely, 2^21957698 is an apocalyptic number.

21957698 is a deficient number, since it is larger than the sum of its proper divisors (16982782).

21957698 is a wasteful number, since it uses less digits than its factorization.

21957698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54121.

The product of its digits is 272160, while the sum is 47.

The square root of 21957698 is about 4685.9041816922. The cubic root of 21957698 is about 280.0242240947.

The spelling of 21957698 in words is "twenty-one million, nine hundred fifty-seven thousand, six hundred ninety-eight".