721864690 has 16 divisors (see below), whose sum is σ = 1299976128. Its totient is φ = 288608176.

The previous prime is 721864673. The next prime is 721864697. The reversal of 721864690 is 96468127.

It is a super-2 number, since 2×721864690² = 1042177261337592200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (721864697) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6339 + ... + 38521.

It is an arithmetic number, because the mean of its divisors is an integer number (81248508).

Almost surely, 2^721864690 is an apocalyptic number.

721864690 is a deficient number, since it is larger than the sum of its proper divisors (578111438).

721864690 is a wasteful number, since it uses less digits than its factorization.

721864690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34433.

The product of its (nonzero) digits is 145152, while the sum is 43.

The square root of 721864690 is about 26867.5397087266. The cubic root of 721864690 is about 897.0540258873.

The spelling of 721864690 in words is "seven hundred twenty-one million, eight hundred sixty-four thousand, six hundred ninety".