721861690 has 32 divisors (see below), whose sum is σ = 1418726016. Its totient is φ = 262263360.

The previous prime is 721861669. The next prime is 721861709. The reversal of 721861690 is 96168127.

721861690 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×721861690² = 1042168598979312200, which contains 22 as substring.

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, 167604 + ... + 171856.

It is an arithmetic number, because the mean of its divisors is an integer number (44335188).

Almost surely, 2^721861690 is an apocalyptic number.

721861690 is a deficient number, since it is larger than the sum of its proper divisors (696864326).

721861690 is a wasteful number, since it uses less digits than its factorization.

721861690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5814.

The product of its (nonzero) digits is 36288, while the sum is 40.

The square root of 721861690 is about 26867.4838792173. The cubic root of 721861690 is about 897.0527831955.

The spelling of 721861690 in words is "seven hundred twenty-one million, eight hundred sixty-one thousand, six hundred ninety".