21937087 has 2 divisors, whose sum is σ = 21937088. Its totient is φ = 21937086.

The previous prime is 21937081. The next prime is 21937117. The reversal of 21937087 is 78073912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21937087 - 2¹⁵ = 21904319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21937081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10968543 + 10968544.

It is an arithmetic number, because the mean of its divisors is an integer number (10968544).

Almost surely, 2^21937087 is an apocalyptic number.

21937087 is a deficient number, since it is larger than the sum of its proper divisors (1).

21937087 is an equidigital number, since it uses as much as digits as its factorization.

21937087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 21937087 is about 4683.7044099729. The cubic root of 21937087 is about 279.9365800242.

The spelling of 21937087 in words is "twenty-one million, nine hundred thirty-seven thousand, eighty-seven".