72755721 has 12 divisors (see below), whose sum is σ = 105723072. Its totient is φ = 48212376.

The previous prime is 72755713. The next prime is 72755741. The reversal of 72755721 is 12755727.

It is not a de Polignac number, because 72755721 - 2³ = 72755713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (72755701) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22701 + ... + 25706.

It is an arithmetic number, because the mean of its divisors is an integer number (8810256).

Almost surely, 2^72755721 is an apocalyptic number.

It is an amenable number.

72755721 is a deficient number, since it is larger than the sum of its proper divisors (32967351).

72755721 is a wasteful number, since it uses less digits than its factorization.

72755721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48580 (or 48577 counting only the distinct ones).

The product of its digits is 34300, while the sum is 36.

The square root of 72755721 is about 8529.6964189823. The cubic root of 72755721 is about 417.4672229757.

It can be divided in two parts, 7275 and 5721, that added together give a square (12996 = 114²).

The spelling of 72755721 in words is "seventy-two million, seven hundred fifty-five thousand, seven hundred twenty-one".