21455037 has 20 divisors (see below), whose sum is σ = 33937596. Its totient is φ = 13461120.

The previous prime is 21455033. The next prime is 21455039. The reversal of 21455037 is 73055412.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 11758041 + 9696996 = 3429^2 + 3114^2 .

It is not a de Polignac number, because 21455037 - 2² = 21455033 is a prime.

It is a super-2 number, since 2×21455037² = 920637225342738, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 21455037.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21455033) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6414 + ... + 9167.

Almost surely, 2^21455037 is an apocalyptic number.

21455037 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21455037 is a deficient number, since it is larger than the sum of its proper divisors (12482559).

21455037 is a wasteful number, since it uses less digits than its factorization.

21455037 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15610 (or 15601 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 21455037 is about 4631.9582252002. The cubic root of 21455037 is about 277.8709137942.

The spelling of 21455037 in words is "twenty-one million, four hundred fifty-five thousand, thirty-seven".