691408556 has 24 divisors (see below), whose sum is σ = 1276012080. Its totient is φ = 326901312.

The previous prime is 691408541. The next prime is 691408559. The reversal of 691408556 is 655804196.

It is not an unprimeable number, because it can be changed into a prime (691408559) 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, 34166 + ... + 50498.

It is an arithmetic number, because the mean of its divisors is an integer number (53167170).

Almost surely, 2^691408556 is an apocalyptic number.

It is an amenable number.

691408556 is a deficient number, since it is larger than the sum of its proper divisors (584603524).

691408556 is a wasteful number, since it uses less digits than its factorization.

691408556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16913 (or 16911 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 44.

The square root of 691408556 is about 26294.6488092159. The cubic root of 691408556 is about 884.2564774527.

The spelling of 691408556 in words is "six hundred ninety-one million, four hundred eight thousand, five hundred fifty-six".