21315155371 has 2 divisors, whose sum is σ = 21315155372. Its totient is φ = 21315155370.

The previous prime is 21315155359. The next prime is 21315155417. The reversal of 21315155371 is 17355151312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21315155371 - 2⁹ = 21315154859 is a prime.

It is not a weakly prime, because it can be changed into another prime (21315155311) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10657577685 + 10657577686.

It is an arithmetic number, because the mean of its divisors is an integer number (10657577686).

Almost surely, 2^21315155371 is an apocalyptic number.

21315155371 is a deficient number, since it is larger than the sum of its proper divisors (1).

21315155371 is an equidigital number, since it uses as much as digits as its factorization.

21315155371 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15750, while the sum is 34.

The spelling of 21315155371 in words is "twenty-one billion, three hundred fifteen million, one hundred fifty-five thousand, three hundred seventy-one".