721117766042520 has 1024 divisors, whose sum is σ = 2834200461312000. Its totient is φ = 142469581363200.

The previous prime is 721117766042473. The next prime is 721117766042539. The reversal of 721117766042520 is 25240667711127.

It is a super-2 number, since 2×721117766042520² (a number of 31 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 2228406091 + ... + 2228729669.

It is an arithmetic number, because the mean of its divisors is an integer number (2767773888000).

Almost surely, 2^{721117766042520} is an apocalyptic number.

721117766042520 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721117766042520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1417100230656000).

721117766042520 is an abundant number, since it is smaller than the sum of its proper divisors (2113082695269480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721117766042520 is a wasteful number, since it uses less digits than its factorization.

721117766042520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323804 (or 323800 counting only the distinct ones).

The product of its (nonzero) digits is 1975680, while the sum is 51.

The spelling of 721117766042520 in words is "seven hundred twenty-one trillion, one hundred seventeen billion, seven hundred sixty-six million, forty-two thousand, five hundred twenty".