691068672 has 378 divisors, whose sum is σ = 2470905752. Its totient is φ = 188863488.

The previous prime is 691068671. The next prime is 691068673. The reversal of 691068672 is 276860196.

It is an interprime number because it is at equal distance from previous prime (691068671) and next prime (691068673).

It is a tau number, because it is divible by the number of its divisors (378).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691068671) by changing a digit.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 30046453 + ... + 30046475.

Almost surely, 2^691068672 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 691068672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1235452876).

691068672 is an abundant number, since it is smaller than the sum of its proper divisors (1779837080).

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

691068672 is an frugal number, since it uses more digits than its factorization.

691068672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 35 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 691068672 is about 26288.1850267378. The cubic root of 691068672 is about 884.1115588480. Note that the first 3 decimals are identical.

The spelling of 691068672 in words is "six hundred ninety-one million, sixty-eight thousand, six hundred seventy-two".