21700628 has 12 divisors (see below), whose sum is σ = 38599092. Its totient is φ = 10672320.

The previous prime is 21700621. The next prime is 21700631. The reversal of 21700628 is 82600712.

It can be written as a sum of positive squares in 2 ways, for example, as 6240004 + 15460624 = 2498^2 + 3932^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21700597 and 21700606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21700621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44225 + ... + 44712.

It is an arithmetic number, because the mean of its divisors is an integer number (3216591).

Almost surely, 2^21700628 is an apocalyptic number.

It is an amenable number.

21700628 is a deficient number, since it is larger than the sum of its proper divisors (16898464).

21700628 is a wasteful number, since it uses less digits than its factorization.

21700628 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89002 (or 89000 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 21700628 is about 4658.3932852433. The cubic root of 21700628 is about 278.9271358993.

The spelling of 21700628 in words is "twenty-one million, seven hundred thousand, six hundred twenty-eight".