9991515559028 has 6 divisors (see below), whose sum is σ = 17485152228306. Its totient is φ = 4995757779512.

The previous prime is 9991515559019. The next prime is 9991515559097. The reversal of 9991515559028 is 8209555151999.

It can be written as a sum of positive squares in only one way, i.e., 8770375636324 + 1221139922704 = 2961482^2 + 1105052^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1248939444875 + ... + 1248939444882.

It is an arithmetic number, because the mean of its divisors is an integer number (2914192038051).

Almost surely, 2^{9991515559028} is an apocalyptic number.

It is an amenable number.

9991515559028 is a deficient number, since it is larger than the sum of its proper divisors (7493636669278).

9991515559028 is a wasteful number, since it uses less digits than its factorization.

9991515559028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2497878889761 (or 2497878889759 counting only the distinct ones).

The product of its (nonzero) digits is 65610000, while the sum is 68.

The spelling of 9991515559028 in words is "nine trillion, nine hundred ninety-one billion, five hundred fifteen million, five hundred fifty-nine thousand, twenty-eight".