72391771 has 2 divisors, whose sum is σ = 72391772. Its totient is φ = 72391770.

The previous prime is 72391699. The next prime is 72391777. The reversal of 72391771 is 17719327.

It is a strong prime.

It is an emirp because it is prime and its reverse (17719327) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72391771 - 2¹³ = 72383579 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 72391771.

It is not a weakly prime, because it can be changed into another prime (72391777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36195885 + 36195886.

It is an arithmetic number, because the mean of its divisors is an integer number (36195886).

Almost surely, 2^72391771 is an apocalyptic number.

72391771 is a deficient number, since it is larger than the sum of its proper divisors (1).

72391771 is an equidigital number, since it uses as much as digits as its factorization.

72391771 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18522, while the sum is 37.

The square root of 72391771 is about 8508.3353836106. The cubic root of 72391771 is about 416.7699524926.

The spelling of 72391771 in words is "seventy-two million, three hundred ninety-one thousand, seven hundred seventy-one".