21251037 has 24 divisors (see below), whose sum is σ = 30493696. Its totient is φ = 13160448.

The previous prime is 21251023. The next prime is 21251053. The reversal of 21251037 is 73015212.

It is not a de Polignac number, because 21251037 - 2¹⁸ = 20988893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251017) 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, 110013 + ... + 110205.

Almost surely, 2^21251037 is an apocalyptic number.

It is an amenable number.

21251037 is a deficient number, since it is larger than the sum of its proper divisors (9242659).

21251037 is a wasteful number, since it uses less digits than its factorization.

21251037 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 357 (or 340 counting only the distinct ones).

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21251037 is about 4609.8847057166. The cubic root of 21251037 is about 276.9874183531.

Adding to 21251037 its reverse (73015212), we get a palindrome (94266249).

The spelling of 21251037 in words is "twenty-one million, two hundred fifty-one thousand, thirty-seven".