99990731 has 2 divisors, whose sum is σ = 99990732. Its totient is φ = 99990730.

The previous prime is 99990703. The next prime is 99990739. The reversal of 99990731 is 13709999.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (13709999) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99990731 is a prime.

It is a super-2 number, since 2×99990731² = 19996292571828722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (99990739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49995365 + 49995366.

It is an arithmetic number, because the mean of its divisors is an integer number (49995366).

Almost surely, 2^99990731 is an apocalyptic number.

99990731 is a deficient number, since it is larger than the sum of its proper divisors (1).

99990731 is an equidigital number, since it uses as much as digits as its factorization.

99990731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 137781, while the sum is 47.

The square root of 99990731 is about 9999.5365392602. The cubic root of 99990731 is about 464.1445419559.

The spelling of 99990731 in words is "ninety-nine million, nine hundred ninety thousand, seven hundred thirty-one".