72697909 has 4 divisors (see below), whose sum is σ = 73889740. Its totient is φ = 71506080.

The previous prime is 72697897. The next prime is 72697921. The reversal of 72697909 is 90979627.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90979627 = 89 ⋅1022243.

It is an interprime number because it is at equal distance from previous prime (72697897) and next prime (72697921).

It can be written as a sum of positive squares in 2 ways, for example, as 4635409 + 68062500 = 2153^2 + 8250^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72697909 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 (72697979) 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, 595824 + ... + 595945.

It is an arithmetic number, because the mean of its divisors is an integer number (18472435).

Almost surely, 2^72697909 is an apocalyptic number.

It is an amenable number.

72697909 is a deficient number, since it is larger than the sum of its proper divisors (1191831).

72697909 is a wasteful number, since it uses less digits than its factorization.

72697909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1191830.

The product of its (nonzero) digits is 428652, while the sum is 49.

The square root of 72697909 is about 8526.3068793001. The cubic root of 72697909 is about 417.3566199419.

The spelling of 72697909 in words is "seventy-two million, six hundred ninety-seven thousand, nine hundred nine".