721689701 has 4 divisors (see below), whose sum is σ = 721871904. Its totient is φ = 721507500.

The previous prime is 721689677. The next prime is 721689707. The reversal of 721689701 is 107986127.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 721689701 - 2⁶ = 721689637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721689707) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 85025 + ... + 93126.

It is an arithmetic number, because the mean of its divisors is an integer number (180467976).

Almost surely, 2^721689701 is an apocalyptic number.

It is an amenable number.

721689701 is a deficient number, since it is larger than the sum of its proper divisors (182203).

721689701 is a wasteful number, since it uses less digits than its factorization.

721689701 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182202.

The product of its (nonzero) digits is 42336, while the sum is 41.

The square root of 721689701 is about 26864.2829980627. The cubic root of 721689701 is about 896.9815343363.

The spelling of 721689701 in words is "seven hundred twenty-one million, six hundred eighty-nine thousand, seven hundred one".