15887458921 has 2 divisors, whose sum is σ = 15887458922. Its totient is φ = 15887458920.

The previous prime is 15887458849. The next prime is 15887458933. The reversal of 15887458921 is 12985478851.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11334583296 + 4552875625 = 106464^2 + 67475^2 .

It is a cyclic number.

It is not a de Polignac number, because 15887458921 - 2²⁷ = 15753241193 is a prime.

It is a super-2 number, since 2×15887458921² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (15887458421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7943729460 + 7943729461.

It is an arithmetic number, because the mean of its divisors is an integer number (7943729461).

Almost surely, 2^15887458921 is an apocalyptic number.

It is an amenable number.

15887458921 is a deficient number, since it is larger than the sum of its proper divisors (1).

15887458921 is an equidigital number, since it uses as much as digits as its factorization.

15887458921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6451200, while the sum is 58.

The spelling of 15887458921 in words is "fifteen billion, eight hundred eighty-seven million, four hundred fifty-eight thousand, nine hundred twenty-one".