21642610 has 16 divisors (see below), whose sum is σ = 42498432. Its totient is φ = 7870000.

The previous prime is 21642601. The next prime is 21642637. The reversal of 21642610 is 1624612.

It is a super-2 number, since 2×21642610² = 936805135224200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (22).

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 7 ways as a sum of consecutive naturals, for example, 98266 + ... + 98485.

It is an arithmetic number, because the mean of its divisors is an integer number (2656152).

Almost surely, 2^21642610 is an apocalyptic number.

21642610 is a deficient number, since it is larger than the sum of its proper divisors (20855822).

21642610 is a wasteful number, since it uses less digits than its factorization.

21642610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196769.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 21642610 is about 4652.1618630482. The cubic root of 21642610 is about 278.6783376012.

It can be divided in two parts, 2164 and 2610, that added together give a palindrome (4774).

The spelling of 21642610 in words is "twenty-one million, six hundred forty-two thousand, six hundred ten".