21837087 has 24 divisors (see below), whose sum is σ = 33668400. Its totient is φ = 13971888.

The previous prime is 21837073. The next prime is 21837089. The reversal of 21837087 is 78073812.

It is not a de Polignac number, because 21837087 - 2¹⁰ = 21836063 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21837089) 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, 130678 + ... + 130844.

It is an arithmetic number, because the mean of its divisors is an integer number (1402850).

Almost surely, 2^21837087 is an apocalyptic number.

21837087 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21837087 is a deficient number, since it is larger than the sum of its proper divisors (11831313).

21837087 is an equidigital number, since it uses as much as digits as its factorization.

21837087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372 (or 199 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The square root of 21837087 is about 4673.0169055975. The cubic root of 21837087 is about 279.5105693096.

The spelling of 21837087 in words is "twenty-one million, eight hundred thirty-seven thousand, eighty-seven".