691553531 has 2 divisors, whose sum is σ = 691553532. Its totient is φ = 691553530.

The previous prime is 691553501. The next prime is 691553537. The reversal of 691553531 is 135355196.

691553531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691553531 - 2¹⁰ = 691552507 is a prime.

It is a super-2 number, since 2×691553531² = 956492572477135922, which contains 22 as substring.

It is equal to p_35838317 and since 691553531 and 35838317 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (691553537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345776765 + 345776766.

It is an arithmetic number, because the mean of its divisors is an integer number (345776766).

Almost surely, 2^691553531 is an apocalyptic number.

691553531 is a deficient number, since it is larger than the sum of its proper divisors (1).

691553531 is an equidigital number, since it uses as much as digits as its factorization.

691553531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60750, while the sum is 38.

The square root of 691553531 is about 26297.4054043360. The cubic root of 691553531 is about 884.3182769597.

The spelling of 691553531 in words is "six hundred ninety-one million, five hundred fifty-three thousand, five hundred thirty-one".