72391757 has 4 divisors (see below), whose sum is σ = 72454236. Its totient is φ = 72329280.

The previous prime is 72391699. The next prime is 72391771. The reversal of 72391757 is 75719327.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75719327 = 179 ⋅423013.

It can be written as a sum of positive squares in 2 ways, for example, as 45414121 + 26977636 = 6739^2 + 5194^2 .

It is a cyclic number.

It is not a de Polignac number, because 72391757 - 2¹⁰ = 72390733 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72391777) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29468 + ... + 31829.

It is an arithmetic number, because the mean of its divisors is an integer number (18113559).

Almost surely, 2^72391757 is an apocalyptic number.

It is an amenable number.

72391757 is a deficient number, since it is larger than the sum of its proper divisors (62479).

72391757 is a wasteful number, since it uses less digits than its factorization.

72391757 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62478.

The product of its digits is 92610, while the sum is 41.

The square root of 72391757 is about 8508.3345608879. The cubic root of 72391757 is about 416.7699256259.

The spelling of 72391757 in words is "seventy-two million, three hundred ninety-one thousand, seven hundred fifty-seven".