21708452 has 6 divisors (see below), whose sum is σ = 37989798. Its totient is φ = 10854224.

The previous prime is 21708451. The next prime is 21708499. The reversal of 21708452 is 25480712.

It can be written as a sum of positive squares in only one way, i.e., 12503296 + 9205156 = 3536^2 + 3034^2 .

It is not an unprimeable number, because it can be changed into a prime (21708451) by changing a digit.

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 as a sum of consecutive naturals, namely, 2713553 + ... + 2713560.

It is an arithmetic number, because the mean of its divisors is an integer number (6331633).

Almost surely, 2^21708452 is an apocalyptic number.

It is an amenable number.

21708452 is a deficient number, since it is larger than the sum of its proper divisors (16281346).

21708452 is a wasteful number, since it uses less digits than its factorization.

21708452 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5427117 (or 5427115 counting only the distinct ones).

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 21708452 is about 4659.2329840865. The cubic root of 21708452 is about 278.9606535727.

The spelling of 21708452 in words is "twenty-one million, seven hundred eight thousand, four hundred fifty-two".