21470291 has 2 divisors, whose sum is σ = 21470292. Its totient is φ = 21470290.

The previous prime is 21470279. The next prime is 21470311. The reversal of 21470291 is 19207412.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21470291 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21470291.

It is not a weakly prime, because it can be changed into another prime (21470261) 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 as a sum of consecutive naturals, namely, 10735145 + 10735146.

It is an arithmetic number, because the mean of its divisors is an integer number (10735146).

Almost surely, 2^21470291 is an apocalyptic number.

21470291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21470291 is an equidigital number, since it uses as much as digits as its factorization.

21470291 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21470291 is about 4633.6045364273. The cubic root of 21470291 is about 277.9367513065.

The spelling of 21470291 in words is "twenty-one million, four hundred seventy thousand, two hundred ninety-one".