721713537 has 16 divisors (see below), whose sum is σ = 1125480000. Its totient is φ = 455818752.

The previous prime is 721713533. The next prime is 721713541. The reversal of 721713537 is 735317127.

It is an interprime number because it is at equal distance from previous prime (721713533) and next prime (721713541).

It is not a de Polignac number, because 721713537 - 2² = 721713533 is a prime.

It is not an unprimeable number, because it can be changed into a prime (721713533) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 702912 + ... + 703937.

It is an arithmetic number, because the mean of its divisors is an integer number (70342500).

Almost surely, 2^721713537 is an apocalyptic number.

It is an amenable number.

721713537 is a deficient number, since it is larger than the sum of its proper divisors (403766463).

721713537 is a wasteful number, since it uses less digits than its factorization.

721713537 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1406877 (or 1406871 counting only the distinct ones).

The product of its digits is 30870, while the sum is 36.

The square root of 721713537 is about 26864.7266317750. The cubic root of 721713537 is about 896.9914094098.

The spelling of 721713537 in words is "seven hundred twenty-one million, seven hundred thirteen thousand, five hundred thirty-seven".