397808720 has 20 divisors (see below), whose sum is σ = 924905460. Its totient is φ = 159123456.

The previous prime is 397808657. The next prime is 397808731. The reversal of 397808720 is 27808793.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 235806736 + 162001984 = 15356^2 + 12728^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2486225 + ... + 2486384.

It is an arithmetic number, because the mean of its divisors is an integer number (46245273).

Almost surely, 2^397808720 is an apocalyptic number.

It is an amenable number.

397808720 is an abundant number, since it is smaller than the sum of its proper divisors (527096740).

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

397808720 is a wasteful number, since it uses less digits than its factorization.

397808720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4972622 (or 4972616 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 44.

The square root of 397808720 is about 19945.1427671000. The cubic root of 397808720 is about 735.4583779046.

The spelling of 397808720 in words is "three hundred ninety-seven million, eight hundred eight thousand, seven hundred twenty".