721537521040 has 80 divisors (see below), whose sum is σ = 1921424199552. Its totient is φ = 246842883072.

The previous prime is 721537520989. The next prime is 721537521079. The reversal of 721537521040 is 40125735127.

It is a tau number, because it is divible by the number of its divisors (80).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1153774 + ... + 1665613.

Almost surely, 2^721537521040 is an apocalyptic number.

721537521040 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

721537521040 is an abundant number, since it is smaller than the sum of its proper divisors (1199886678512).

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

721537521040 is a wasteful number, since it uses less digits than its factorization.

721537521040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2819864 (or 2819858 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 37.

The spelling of 721537521040 in words is "seven hundred twenty-one billion, five hundred thirty-seven million, five hundred twenty-one thousand, forty".