21607643 has 8 divisors (see below), whose sum is σ = 22012416. Its totient is φ = 21205800.

The previous prime is 21607633. The next prime is 21607657. The reversal of 21607643 is 34670612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21607643 - 2⁸ = 21607387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21607613) 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, 18680 + ... + 19802.

It is an arithmetic number, because the mean of its divisors is an integer number (2751552).

Almost surely, 2^21607643 is an apocalyptic number.

21607643 is a deficient number, since it is larger than the sum of its proper divisors (404773).

21607643 is a wasteful number, since it uses less digits than its factorization.

21607643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1465.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 21607643 is about 4648.4021986055. The cubic root of 21607643 is about 278.5281739797.

The spelling of 21607643 in words is "twenty-one million, six hundred seven thousand, six hundred forty-three".