721173054690 has 120 divisors (see below), whose sum is σ = 2062545898140. Its totient is φ = 174829512000.

The previous prime is 721173054683. The next prime is 721173054731. The reversal of 721173054690 is 96450371127.

721173054690 is a `hidden beast` number, since 7 + 2 + 1 + 17 + 3 + 0 + 546 + 90 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 713519779401 + 7653275289 = 844701^2 + 87483^2 .

It is a super-2 number, since 2×721173054690² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

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 59 ways as a sum of consecutive naturals, for example, 1044040 + ... + 1591340.

Almost surely, 2^721173054690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721173054690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1031272949070).

721173054690 is an abundant number, since it is smaller than the sum of its proper divisors (1341372843450).

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

721173054690 is a wasteful number, since it uses less digits than its factorization.

721173054690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547358 (or 547322 counting only the distinct ones).

The product of its (nonzero) digits is 317520, while the sum is 45.

The spelling of 721173054690 in words is "seven hundred twenty-one billion, one hundred seventy-three million, fifty-four thousand, six hundred ninety".