72809657 has 4 divisors (see below), whose sum is σ = 77092596. Its totient is φ = 68526720.

The previous prime is 72809617. The next prime is 72809663. The reversal of 72809657 is 75690827.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 40819321 + 31990336 = 6389^2 + 5656^2 .

It is a cyclic number.

It is not a de Polignac number, because 72809657 - 2⁶ = 72809593 is a prime.

It is a super-3 number, since 3×72809657³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72809617) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2141444 + ... + 2141477.

It is an arithmetic number, because the mean of its divisors is an integer number (19273149).

Almost surely, 2^72809657 is an apocalyptic number.

It is an amenable number.

72809657 is a deficient number, since it is larger than the sum of its proper divisors (4282939).

72809657 is a wasteful number, since it uses less digits than its factorization.

72809657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4282938.

The product of its (nonzero) digits is 211680, while the sum is 44.

The square root of 72809657 is about 8532.8574932434. The cubic root of 72809657 is about 417.5703578223.

The spelling of 72809657 in words is "seventy-two million, eight hundred nine thousand, six hundred fifty-seven".