691636340736 has 360 divisors, whose sum is σ = 2270810972430. Its totient is φ = 209580687360.

The previous prime is 691636340683. The next prime is 691636340777. The reversal of 691636340736 is 637043636196.

691636340736 is a `hidden beast` number, since 6 + 91 + 63 + 63 + 407 + 36 = 666.

It can be written as a sum of positive squares in only one way, i.e., 554250470400 + 137385870336 = 744480^2 + 370656^2 .

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 20055220 + ... + 20089676.

Almost surely, 2^691636340736 is an apocalyptic number.

691636340736 is a gapful number since it is divisible by the number (66) 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 691636340736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1135405486215).

691636340736 is an abundant number, since it is smaller than the sum of its proper divisors (1579174631694).

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

691636340736 is a wasteful number, since it uses less digits than its factorization.

691636340736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34513 (or 34473 counting only the distinct ones).

The product of its (nonzero) digits is 8817984, while the sum is 54.

The spelling of 691636340736 in words is "six hundred ninety-one billion, six hundred thirty-six million, three hundred forty thousand, seven hundred thirty-six".