691372643 has 16 divisors (see below), whose sum is σ = 792802080. Its totient is φ = 597259776.

The previous prime is 691372631. The next prime is 691372667. The reversal of 691372643 is 346273196.

It is not a de Polignac number, because 691372643 - 2¹² = 691368547 is a prime.

It is a super-2 number, since 2×691372643² = 955992262977610898, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 691372643.

It is not an unprimeable number, because it can be changed into a prime (691372603) 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 15 ways as a sum of consecutive naturals, for example, 30821 + ... + 48297.

It is an arithmetic number, because the mean of its divisors is an integer number (49550130).

Almost surely, 2^691372643 is an apocalyptic number.

691372643 is a deficient number, since it is larger than the sum of its proper divisors (101429437).

691372643 is a wasteful number, since it uses less digits than its factorization.

691372643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17686.

The product of its digits is 163296, while the sum is 41.

The square root of 691372643 is about 26293.9659047470. The cubic root of 691372643 is about 884.2411672320.

The spelling of 691372643 in words is "six hundred ninety-one million, three hundred seventy-two thousand, six hundred forty-three".