21620436 has 24 divisors (see below), whose sum is σ = 50717184. Its totient is φ = 7168320.

The previous prime is 21620419. The next prime is 21620453. The reversal of 21620436 is 63402612.

It is an interprime number because it is at equal distance from previous prime (21620419) and next prime (21620453).

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 7 ways as a sum of consecutive naturals, for example, 2425 + ... + 7008.

It is an arithmetic number, because the mean of its divisors is an integer number (2113216).

Almost surely, 2^21620436 is an apocalyptic number.

It is an amenable number.

21620436 is an abundant number, since it is smaller than the sum of its proper divisors (29096748).

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

21620436 is a wasteful number, since it uses less digits than its factorization.

21620436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9631 (or 9629 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

The square root of 21620436 is about 4649.7780592196. The cubic root of 21620436 is about 278.5831315080.

The spelling of 21620436 in words is "twenty-one million, six hundred twenty thousand, four hundred thirty-six".