721664136133366 has 8 divisors (see below), whose sum is σ = 1082549982202920. Its totient is φ = 360814142065728.

The previous prime is 721664136133337. The next prime is 721664136133481. The reversal of 721664136133366 is 663331631466127.

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

It is a super-2 number, since 2×721664136133366² (a number of 31 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 721664136133366.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8962950156 + ... + 8963030671.

It is an arithmetic number, because the mean of its divisors is an integer number (135318747775365).

Almost surely, 2^{721664136133366} is an apocalyptic number.

721664136133366 is a deficient number, since it is larger than the sum of its proper divisors (360885846069554).

721664136133366 is a wasteful number, since it uses less digits than its factorization.

721664136133366 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17926000958.

The product of its digits is 35271936, while the sum is 58.

The spelling of 721664136133366 in words is "seven hundred twenty-one trillion, six hundred sixty-four billion, one hundred thirty-six million, one hundred thirty-three thousand, three hundred sixty-six".