21370491 has 12 divisors (see below), whose sum is σ = 30914832. Its totient is φ = 14225616.

The previous prime is 21370483. The next prime is 21370499. The reversal of 21370491 is 19407312.

It is an interprime number because it is at equal distance from previous prime (21370483) and next prime (21370499).

It is not a de Polignac number, because 21370491 - 2³ = 21370483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21370499) 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 11 ways as a sum of consecutive naturals, for example, 6645 + ... + 9321.

It is an arithmetic number, because the mean of its divisors is an integer number (2576236).

Almost surely, 2^21370491 is an apocalyptic number.

21370491 is a deficient number, since it is larger than the sum of its proper divisors (9544341).

21370491 is a wasteful number, since it uses less digits than its factorization.

21370491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3570 (or 3567 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 21370491 is about 4622.8228389156. The cubic root of 21370491 is about 277.5054393869.

The spelling of 21370491 in words is "twenty-one million, three hundred seventy thousand, four hundred ninety-one".