691041213 has 12 divisors (see below), whose sum is σ = 1035140288. Its totient is φ = 460693980.

The previous prime is 691041199. The next prime is 691041223. The reversal of 691041213 is 312140196.

It is a de Polignac number, because none of the positive numbers 2^k-691041213 is a prime.

It is a super-2 number, since 2×691041213² = 955075916129022738, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691041223) 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, 1421653 + ... + 1422138.

Almost surely, 2^691041213 is an apocalyptic number.

It is an amenable number.

691041213 is a deficient number, since it is larger than the sum of its proper divisors (344099075).

691041213 is an equidigital number, since it uses as much as digits as its factorization.

691041213 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843806 (or 2843794 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 691041213 is about 26287.6627527059. The cubic root of 691041213 is about 884.0998488971.

The spelling of 691041213 in words is "six hundred ninety-one million, forty-one thousand, two hundred thirteen".