691644953 has 4 divisors (see below), whose sum is σ = 701968080. Its totient is φ = 681321828.

The previous prime is 691644929. The next prime is 691644971. The reversal of 691644953 is 359446196.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 691644953 - 2²⁸ = 423209497 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 691644898 and 691644907.

It is not an unprimeable number, because it can be changed into a prime (691644913) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5161463 + ... + 5161596.

It is an arithmetic number, because the mean of its divisors is an integer number (175492020).

Almost surely, 2^691644953 is an apocalyptic number.

It is an amenable number.

691644953 is a deficient number, since it is larger than the sum of its proper divisors (10323127).

691644953 is a wasteful number, since it uses less digits than its factorization.

691644953 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10323126.

The product of its digits is 699840, while the sum is 47.

The square root of 691644953 is about 26299.1435792119. The cubic root of 691644953 is about 884.3572436146.

The spelling of 691644953 in words is "six hundred ninety-one million, six hundred forty-four thousand, nine hundred fifty-three".