691638472 has 64 divisors (see below), whose sum is σ = 1581016320. Its totient is φ = 276891648.

The previous prime is 691638461. The next prime is 691638509. The reversal of 691638472 is 274836196.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 127773 + ... + 133075.

It is an arithmetic number, because the mean of its divisors is an integer number (24703380).

Almost surely, 2^691638472 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691638472, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (790508160).

691638472 is an abundant number, since it is smaller than the sum of its proper divisors (889377848).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691638472 is a wasteful number, since it uses less digits than its factorization.

691638472 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5470 (or 5466 counting only the distinct ones).

The product of its digits is 435456, while the sum is 46.

The square root of 691638472 is about 26299.0203619831. The cubic root of 691638472 is about 884.3544813413.

The spelling of 691638472 in words is "six hundred ninety-one million, six hundred thirty-eight thousand, four hundred seventy-two".