21653694 has 24 divisors (see below), whose sum is σ = 47005920. Its totient is φ = 7204128.

The previous prime is 21653677. The next prime is 21653707. The reversal of 21653694 is 49635612.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 13819 + ... + 15305.

It is an arithmetic number, because the mean of its divisors is an integer number (1958580).

Almost surely, 2^21653694 is an apocalyptic number.

21653694 is an abundant number, since it is smaller than the sum of its proper divisors (25352226).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21653694 is a wasteful number, since it uses less digits than its factorization.

21653694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2304 (or 2301 counting only the distinct ones).

The product of its digits is 38880, while the sum is 36.

The square root of 21653694 is about 4653.3529846767. The cubic root of 21653694 is about 278.7259033914.

The spelling of 21653694 in words is "twenty-one million, six hundred fifty-three thousand, six hundred ninety-four".