21037423 has 18 divisors (see below), whose sum is σ = 23952768. Its totient is φ = 18461520.

The previous prime is 21037411. The next prime is 21037439. The reversal of 21037423 is 32473012.

It is a de Polignac number, because none of the positive numbers 2^k-21037423 is a prime.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21037394 and 21037403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21007423) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 165586 + ... + 165712.

Almost surely, 2^21037423 is an apocalyptic number.

21037423 is a deficient number, since it is larger than the sum of its proper divisors (2915345).

21037423 is a wasteful number, since it uses less digits than its factorization.

21037423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 223 (or 175 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21037423 is about 4586.6570615210. The cubic root of 21037423 is about 276.0562048597.

The spelling of 21037423 in words is "twenty-one million, thirty-seven thousand, four hundred twenty-three".