21397108 has 6 divisors (see below), whose sum is σ = 37444946. Its totient is φ = 10698552.

The previous prime is 21397093. The next prime is 21397139. The reversal of 21397108 is 80179312.

It can be written as a sum of positive squares in only one way, i.e., 18766224 + 2630884 = 4332^2 + 1622^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21397108.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2674635 + ... + 2674642.

Almost surely, 2^21397108 is an apocalyptic number.

It is an amenable number.

21397108 is a deficient number, since it is larger than the sum of its proper divisors (16047838).

21397108 is a wasteful number, since it uses less digits than its factorization.

21397108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5349281 (or 5349279 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 21397108 is about 4625.7008117690. The cubic root of 21397108 is about 277.6206028277.

The spelling of 21397108 in words is "twenty-one million, three hundred ninety-seven thousand, one hundred eight".