721574778261 has 8 divisors (see below), whose sum is σ = 962886381120. Its totient is φ = 480656513792.

The previous prime is 721574778251. The next prime is 721574778263. The reversal of 721574778261 is 162877475127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 721574778261 - 2⁵ = 721574778229 is a prime.

It is a super-2 number, since 2×721574778261² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721574778263) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 98330316 + ... + 98337653.

It is an arithmetic number, because the mean of its divisors is an integer number (120360797640).

Almost surely, 2^721574778261 is an apocalyptic number.

It is an amenable number.

721574778261 is a deficient number, since it is larger than the sum of its proper divisors (241311602859).

721574778261 is a wasteful number, since it uses less digits than its factorization.

721574778261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196669195.

The product of its digits is 9219840, while the sum is 57.

The spelling of 721574778261 in words is "seven hundred twenty-one billion, five hundred seventy-four million, seven hundred seventy-eight thousand, two hundred sixty-one".