21257037 has 24 divisors (see below), whose sum is σ = 32383104. Its totient is φ = 13410144.

The previous prime is 21257017. The next prime is 21257053. The reversal of 21257037 is 73075212.

It is not a de Polignac number, because 21257037 - 2⁷ = 21256909 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21257037.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21257017) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20823 + ... + 21819.

It is an arithmetic number, because the mean of its divisors is an integer number (1349296).

Almost surely, 2^21257037 is an apocalyptic number.

It is an amenable number.

21257037 is a deficient number, since it is larger than the sum of its proper divisors (11126067).

21257037 is a wasteful number, since it uses less digits than its factorization.

21257037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1129 (or 1126 counting only the distinct ones).

The product of its (nonzero) digits is 2940, while the sum is 27.

The square root of 21257037 is about 4610.5354352830. The cubic root of 21257037 is about 277.0134840321.

The spelling of 21257037 in words is "twenty-one million, two hundred fifty-seven thousand, thirty-seven".