72191957 has 2 divisors, whose sum is σ = 72191958. Its totient is φ = 72191956.

The previous prime is 72191947. The next prime is 72191981. The reversal of 72191957 is 75919127.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52911076 + 19280881 = 7274^2 + 4391^2 .

It is a cyclic number.

It is not a de Polignac number, because 72191957 - 2¹² = 72187861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (72191927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36095978 + 36095979.

It is an arithmetic number, because the mean of its divisors is an integer number (36095979).

Almost surely, 2^72191957 is an apocalyptic number.

It is an amenable number.

72191957 is a deficient number, since it is larger than the sum of its proper divisors (1).

72191957 is an equidigital number, since it uses as much as digits as its factorization.

72191957 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 39690, while the sum is 41.

The square root of 72191957 is about 8496.5850198771. The cubic root of 72191957 is about 416.3861464003.

The spelling of 72191957 in words is "seventy-two million, one hundred ninety-one thousand, nine hundred fifty-seven".