691216438 has 16 divisors (see below), whose sum is σ = 1135783440. Its totient is φ = 312883200.

The previous prime is 691216403. The next prime is 691216439. The reversal of 691216438 is 834612196.

It is a super-2 number, since 2×691216438² = 955560328322815688, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 691216438.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691216439) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59883 + ... + 70486.

It is an arithmetic number, because the mean of its divisors is an integer number (70986465).

Almost surely, 2^691216438 is an apocalyptic number.

691216438 is a deficient number, since it is larger than the sum of its proper divisors (444567002).

691216438 is a wasteful number, since it uses less digits than its factorization.

691216438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130623.

The product of its digits is 62208, while the sum is 40.

The square root of 691216438 is about 26290.9953786463. The cubic root of 691216438 is about 884.1745686586.

The spelling of 691216438 in words is "six hundred ninety-one million, two hundred sixteen thousand, four hundred thirty-eight".