691788420 has 72 divisors (see below), whose sum is σ = 2100571200. Its totient is φ = 184288320.

The previous prime is 691788407. The next prime is 691788443. The reversal of 691788420 is 24887196.

691788420 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 328531 + ... + 330629.

It is an arithmetic number, because the mean of its divisors is an integer number (29174600).

Almost surely, 2^691788420 is an apocalyptic number.

691788420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

691788420 is an abundant number, since it is smaller than the sum of its proper divisors (1408782780).

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

691788420 is a wasteful number, since it uses less digits than its factorization.

691788420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3945 (or 3940 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The square root of 691788420 is about 26301.8710361069. The cubic root of 691788420 is about 884.4183864059.

The spelling of 691788420 in words is "six hundred ninety-one million, seven hundred eighty-eight thousand, four hundred twenty".