691831980 has 108 divisors (see below), whose sum is σ = 2441209680. Its totient is φ = 158131008.

The previous prime is 691831969. The next prime is 691831981. The reversal of 691831980 is 89138196.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691831981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 30400 + ... + 48039.

Almost surely, 2^691831980 is an apocalyptic number.

691831980 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

691831980 is an abundant number, since it is smaller than the sum of its proper divisors (1749377700).

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

691831980 is a wasteful number, since it uses less digits than its factorization.

691831980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78468 (or 78456 counting only the distinct ones).

The product of its (nonzero) digits is 93312, while the sum is 45.

The square root of 691831980 is about 26302.6991010428. The cubic root of 691831980 is about 884.4369491414.

The spelling of 691831980 in words is "six hundred ninety-one million, eight hundred thirty-one thousand, nine hundred eighty".