72691521 has 16 divisors (see below), whose sum is σ = 110953344. Its totient is φ = 41468544.

The previous prime is 72691519. The next prime is 72691537. The reversal of 72691521 is 12519627.

It is not a de Polignac number, because 72691521 - 2¹ = 72691519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72691561) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11661 + ... + 16773.

It is an arithmetic number, because the mean of its divisors is an integer number (6934584).

Almost surely, 2^72691521 is an apocalyptic number.

It is an amenable number.

72691521 is a deficient number, since it is larger than the sum of its proper divisors (38261823).

72691521 is a wasteful number, since it uses less digits than its factorization.

72691521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5800.

The product of its digits is 7560, while the sum is 33.

The square root of 72691521 is about 8525.9322657408. The cubic root of 72691521 is about 417.3443951420.

The spelling of 72691521 in words is "seventy-two million, six hundred ninety-one thousand, five hundred twenty-one".