721978763 has 16 divisors (see below), whose sum is σ = 870206976. Its totient is φ = 590874240.

The previous prime is 721978759. The next prime is 721978771. The reversal of 721978763 is 367879127.

It is not a de Polignac number, because 721978763 - 2² = 721978759 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (721978723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79631 + ... + 88232.

It is an arithmetic number, because the mean of its divisors is an integer number (54387936).

Almost surely, 2^721978763 is an apocalyptic number.

721978763 is a deficient number, since it is larger than the sum of its proper divisors (148228213).

721978763 is a wasteful number, since it uses less digits than its factorization.

721978763 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167914.

The product of its digits is 889056, while the sum is 50.

The square root of 721978763 is about 26869.6625025325. The cubic root of 721978763 is about 897.1012758569.

The spelling of 721978763 in words is "seven hundred twenty-one million, nine hundred seventy-eight thousand, seven hundred sixty-three".