99972157 has 2 divisors, whose sum is σ = 99972158. Its totient is φ = 99972156.

The previous prime is 99972079. The next prime is 99972161. The reversal of 99972157 is 75127999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85729081 + 14243076 = 9259^2 + 3774^2 .

It is an emirp because it is prime and its reverse (75127999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99972157 - 2¹⁹ = 99447869 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99972157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99972857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49986078 + 49986079.

It is an arithmetic number, because the mean of its divisors is an integer number (49986079).

Almost surely, 2^99972157 is an apocalyptic number.

It is an amenable number.

99972157 is a deficient number, since it is larger than the sum of its proper divisors (1).

99972157 is an equidigital number, since it uses as much as digits as its factorization.

99972157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 357210, while the sum is 49.

The square root of 99972157 is about 9998.6077530824. The cubic root of 99972157 is about 464.1158007766.

The spelling of 99972157 in words is "ninety-nine million, nine hundred seventy-two thousand, one hundred fifty-seven".