691801904640 has 1280 divisors, whose sum is σ = 3029771796480. Its totient is φ = 130215444480.

The previous prime is 691801904609. The next prime is 691801904653. The reversal of 691801904640 is 46409108196.

It is a tau number, because it is divible by the number of its divisors (1280).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 691801904640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 258422982 + ... + 258425658.

It is an arithmetic number, because the mean of its divisors is an integer number (2367009216).

Almost surely, 2^691801904640 is an apocalyptic number.

691801904640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691801904640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1514885898240).

691801904640 is an abundant number, since it is smaller than the sum of its proper divisors (2337969891840).

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

691801904640 is a wasteful number, since it uses less digits than its factorization.

691801904640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2763 (or 2747 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 48.

The spelling of 691801904640 in words is "six hundred ninety-one billion, eight hundred one million, nine hundred four thousand, six hundred forty".