72051661 has 16 divisors (see below), whose sum is σ = 83559168. Its totient is φ = 61401600.

The previous prime is 72051643. The next prime is 72051671. The reversal of 72051661 is 16615027.

It is a cyclic number.

It is not a de Polignac number, because 72051661 - 2¹³ = 72043469 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72051601) 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, 57916 + ... + 59146.

It is an arithmetic number, because the mean of its divisors is an integer number (5222448).

Almost surely, 2^72051661 is an apocalyptic number.

It is an amenable number.

72051661 is a deficient number, since it is larger than the sum of its proper divisors (11507507).

72051661 is a wasteful number, since it uses less digits than its factorization.

72051661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1572.

The product of its (nonzero) digits is 2520, while the sum is 28.

The square root of 72051661 is about 8488.3249819973. The cubic root of 72051661 is about 416.1162400914.

Adding to 72051661 its reverse (16615027), we get a palindrome (88666688).

The spelling of 72051661 in words is "seventy-two million, fifty-one thousand, six hundred sixty-one".