691477920 has 288 divisors, whose sum is σ = 2718817920. Its totient is φ = 156764160.

The previous prime is 691477889. The next prime is 691477921. The reversal of 691477920 is 29774196.

691477920 is a `hidden beast` number, since 6 + 91 + 477 + 92 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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

It is not an unprimeable number, because it can be changed into a prime (691477921) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1824291 + ... + 1824669.

It is an arithmetic number, because the mean of its divisors is an integer number (9440340).

Almost surely, 2^691477920 is an apocalyptic number.

691477920 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 691477920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1359408960).

691477920 is an abundant number, since it is smaller than the sum of its proper divisors (2027340000).

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

691477920 is a wasteful number, since it uses less digits than its factorization.

691477920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588 (or 577 counting only the distinct ones).

The product of its (nonzero) digits is 190512, while the sum is 45.

The square root of 691477920 is about 26295.9677517295. The cubic root of 691477920 is about 884.2860468078.

The spelling of 691477920 in words is "six hundred ninety-one million, four hundred seventy-seven thousand, nine hundred twenty".