691919990 has 16 divisors (see below), whose sum is σ = 1288403280. Its totient is φ = 267224160.

The previous prime is 691919981. The next prime is 691920013. The reversal of 691919990 is 99919196.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1192676 + ... + 1193255.

It is an arithmetic number, because the mean of its divisors is an integer number (80525205).

Almost surely, 2^691919990 is an apocalyptic number.

691919990 is a deficient number, since it is larger than the sum of its proper divisors (596483290).

691919990 is a wasteful number, since it uses less digits than its factorization.

691919990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2385967.

The product of its (nonzero) digits is 354294, while the sum is 53.

The square root of 691919990 is about 26304.3720700571. The cubic root of 691919990 is about 884.4744515011.

The spelling of 691919990 in words is "six hundred ninety-one million, nine hundred nineteen thousand, nine hundred ninety".