691056945 has 12 divisors (see below), whose sum is σ = 1197832116. Its totient is φ = 368563680.

The previous prime is 691056941. The next prime is 691056997. The reversal of 691056945 is 549650196.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 355397904 + 335659041 = 18852^2 + 18321^2 .

It is not a de Polignac number, because 691056945 - 2² = 691056941 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 15356821 = 691056945 / (6 + 9 + 1 + 0 + 5 + 6 + 9 + 4 + 5).

It is a self number, because there is not a number n which added to its sum of digits gives 691056945.

It is not an unprimeable number, because it can be changed into a prime (691056941) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7678366 + ... + 7678455.

It is an arithmetic number, because the mean of its divisors is an integer number (99819343).

Almost surely, 2^691056945 is an apocalyptic number.

It is an amenable number.

691056945 is a deficient number, since it is larger than the sum of its proper divisors (506775171).

691056945 is a wasteful number, since it uses less digits than its factorization.

691056945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15356832 (or 15356829 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The square root of 691056945 is about 26287.9619788222. The cubic root of 691056945 is about 884.1065578810.

The spelling of 691056945 in words is "six hundred ninety-one million, fifty-six thousand, nine hundred forty-five".