752920721 has 6 divisors (see below), whose sum is σ = 875846610. Its totient is φ = 645360576.

The previous prime is 752920717. The next prime is 752920747. The reversal of 752920721 is 127029257.

It can be written as a sum of positive squares in only one way, i.e., 689797696 + 63123025 = 26264^2 + 7945^2 .

It is not a de Polignac number, because 752920721 - 2² = 752920717 is a prime.

It is a super-2 number, since 2×752920721² = 1133779224222319682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (752920711) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7682816 + ... + 7682913.

It is an arithmetic number, because the mean of its divisors is an integer number (145974435).

Almost surely, 2^752920721 is an apocalyptic number.

It is an amenable number.

752920721 is a deficient number, since it is larger than the sum of its proper divisors (122925889).

752920721 is a wasteful number, since it uses less digits than its factorization.

752920721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15365743 (or 15365736 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 752920721 is about 27439.4008863167. The cubic root of 752920721 is about 909.7381692476.

Adding to 752920721 its reverse (127029257), we get a palindrome (879949978).

The spelling of 752920721 in words is "seven hundred fifty-two million, nine hundred twenty thousand, seven hundred twenty-one".