721676681 has 32 divisors (see below), whose sum is σ = 847024128. Its totient is φ = 608333440.

The previous prime is 721676671. The next prime is 721676701. The reversal of 721676681 is 186676127.

It is not a de Polignac number, because 721676681 - 2¹⁰ = 721675657 is a prime.

It is a super-2 number, since 2×721676681² = 1041634463798351522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (721676671) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1628846 + ... + 1629288.

It is an arithmetic number, because the mean of its divisors is an integer number (26469504).

Almost surely, 2^721676681 is an apocalyptic number.

It is an amenable number.

721676681 is a deficient number, since it is larger than the sum of its proper divisors (125347447).

721676681 is a wasteful number, since it uses less digits than its factorization.

721676681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 661.

The product of its digits is 169344, while the sum is 44.

The square root of 721676681 is about 26864.0406677774. The cubic root of 721676681 is about 896.9761401575.

The spelling of 721676681 in words is "seven hundred twenty-one million, six hundred seventy-six thousand, six hundred eighty-one".