21620516 has 24 divisors (see below), whose sum is σ = 39427584. Its totient is φ = 10362240.

The previous prime is 21620513. The next prime is 21620531. The reversal of 21620516 is 61502612.

It is a junction number, because it is equal to n+sod(n) for n = 21620491 and 21620500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620513) 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, 13241 + ... + 14783.

It is an arithmetic number, because the mean of its divisors is an integer number (1642816).

Almost surely, 2^21620516 is an apocalyptic number.

It is an amenable number.

21620516 is a deficient number, since it is larger than the sum of its proper divisors (17807068).

21620516 is a wasteful number, since it uses less digits than its factorization.

21620516 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1691 (or 1689 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 21620516 is about 4649.7866617728. The cubic root of 21620516 is about 278.5834751123.

The spelling of 21620516 in words is "twenty-one million, six hundred twenty thousand, five hundred sixteen".