691491457 has 8 divisors (see below), whose sum is σ = 717186600. Its totient is φ = 665919744.

The previous prime is 691491433. The next prime is 691491461. The reversal of 691491457 is 754194196.

It can be written as a sum of positive squares in 4 ways, for example, as 15023376 + 676468081 = 3876^2 + 26009^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 691491457 - 2²⁷ = 557273729 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691491407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19368 + ... + 41929.

It is an arithmetic number, because the mean of its divisors is an integer number (89648325).

Almost surely, 2^691491457 is an apocalyptic number.

It is an amenable number.

691491457 is a deficient number, since it is larger than the sum of its proper divisors (25695143).

691491457 is a wasteful number, since it uses less digits than its factorization.

691491457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61715.

The product of its digits is 272160, while the sum is 46.

The square root of 691491457 is about 26296.2251473477. The cubic root of 691491457 is about 884.2918172991.

The spelling of 691491457 in words is "six hundred ninety-one million, four hundred ninety-one thousand, four hundred fifty-seven".