99031987755661 has 2 divisors, whose sum is σ = 99031987755662. Its totient is φ = 99031987755660.

The previous prime is 99031987755653. The next prime is 99031987755671. The reversal of 99031987755661 is 16655778913099.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 50368388390761 + 48663599364900 = 7097069^2 + 6975930^2 .

It is a cyclic number.

It is not a de Polignac number, because 99031987755661 - 2³ = 99031987755653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99031987755641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49515993877830 + 49515993877831.

It is an arithmetic number, because the mean of its divisors is an integer number (49515993877831).

Almost surely, 2^{99031987755661} is an apocalyptic number.

It is an amenable number.

99031987755661 is a deficient number, since it is larger than the sum of its proper divisors (1).

99031987755661 is an equidigital number, since it uses as much as digits as its factorization.

99031987755661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 771573600, while the sum is 76.

The spelling of 99031987755661 in words is "ninety-nine trillion, thirty-one billion, nine hundred eighty-seven million, seven hundred fifty-five thousand, six hundred sixty-one".