72131987 has 2 divisors, whose sum is σ = 72131988. Its totient is φ = 72131986.

The previous prime is 72131971. The next prime is 72131989. The reversal of 72131987 is 78913127.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 72131987 - 2⁴ = 72131971 is a prime.

Together with 72131989, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72131987.

It is not a weakly prime, because it can be changed into another prime (72131989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36065993 + 36065994.

It is an arithmetic number, because the mean of its divisors is an integer number (36065994).

Almost surely, 2^72131987 is an apocalyptic number.

72131987 is a deficient number, since it is larger than the sum of its proper divisors (1).

72131987 is an equidigital number, since it uses as much as digits as its factorization.

72131987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 72131987 is about 8493.0552217680. The cubic root of 72131987 is about 416.2708168639.

The spelling of 72131987 in words is "seventy-two million, one hundred thirty-one thousand, nine hundred eighty-seven".