721677231551 has 4 divisors (see below), whose sum is σ = 753054502512. Its totient is φ = 690299960592.

The previous prime is 721677231493. The next prime is 721677231557. The reversal of 721677231551 is 155132776127.

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

It is a cyclic number.

It is not a de Polignac number, because 721677231551 - 2³⁴ = 704497362367 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721677231496 and 721677231505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721677231557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15688635446 + ... + 15688635491.

It is an arithmetic number, because the mean of its divisors is an integer number (188263625628).

Almost surely, 2^721677231551 is an apocalyptic number.

721677231551 is a deficient number, since it is larger than the sum of its proper divisors (31377270961).

721677231551 is a wasteful number, since it uses less digits than its factorization.

721677231551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31377270960.

The product of its digits is 617400, while the sum is 47.

The spelling of 721677231551 in words is "seven hundred twenty-one billion, six hundred seventy-seven million, two hundred thirty-one thousand, five hundred fifty-one".