72651681 has 8 divisors (see below), whose sum is σ = 107632160. Its totient is φ = 48434436.

The previous prime is 72651637. The next prime is 72651701. The reversal of 72651681 is 18615627.

It is not a de Polignac number, because 72651681 - 2⁶ = 72651617 is a prime.

It is a super-2 number, since 2×72651681² = 10556533504251522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72651281) 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 7 ways as a sum of consecutive naturals, for example, 1345375 + ... + 1345428.

It is an arithmetic number, because the mean of its divisors is an integer number (13454020).

Almost surely, 2^72651681 is an apocalyptic number.

It is an amenable number.

72651681 is a deficient number, since it is larger than the sum of its proper divisors (34980479).

72651681 is a wasteful number, since it uses less digits than its factorization.

72651681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2690812 (or 2690806 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 72651681 is about 8523.5955441351. The cubic root of 72651681 is about 417.2681366413.

The spelling of 72651681 in words is "seventy-two million, six hundred fifty-one thousand, six hundred eighty-one".