21037437 has 12 divisors (see below), whose sum is σ = 31368064. Its totient is φ = 13572360.

The previous prime is 21037411. The next prime is 21037439. The reversal of 21037437 is 73473012.

It is not a de Polignac number, because 21037437 - 2¹⁰ = 21036413 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21037437.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21037439) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 37423 + ... + 37980.

Almost surely, 2^21037437 is an apocalyptic number.

It is an amenable number.

21037437 is a deficient number, since it is larger than the sum of its proper divisors (10330627).

21037437 is a wasteful number, since it uses less digits than its factorization.

21037437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75440 (or 75437 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 27.

The square root of 21037437 is about 4586.6585876867. The cubic root of 21037437 is about 276.0562660964.

The spelling of 21037437 in words is "twenty-one million, thirty-seven thousand, four hundred thirty-seven".