691440673 has 16 divisors (see below), whose sum is σ = 876193920. Its totient is φ = 529948800.

The previous prime is 691440661. The next prime is 691440721. The reversal of 691440673 is 376044196.

It is a cyclic number.

It is not a de Polignac number, because 691440673 - 2⁹ = 691440161 is a prime.

It is not an unprimeable number, because it can be changed into a prime (691440613) 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, 68908 + ... + 78301.

It is an arithmetic number, because the mean of its divisors is an integer number (54762120).

Almost surely, 2^691440673 is an apocalyptic number.

It is an amenable number.

691440673 is a deficient number, since it is larger than the sum of its proper divisors (184753247).

691440673 is a wasteful number, since it uses less digits than its factorization.

691440673 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147288.

The product of its (nonzero) digits is 108864, while the sum is 40.

The square root of 691440673 is about 26295.2595157378. The cubic root of 691440673 is about 884.2701689357.

The spelling of 691440673 in words is "six hundred ninety-one million, four hundred forty thousand, six hundred seventy-three".