397991780 has 12 divisors (see below), whose sum is σ = 835782780. Its totient is φ = 159196704.

The previous prime is 397991779. The next prime is 397991801. The reversal of 397991780 is 87199793.

It can be written as a sum of positive squares in 2 ways, for example, as 251920384 + 146071396 = 15872^2 + 12086^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9949775 + ... + 9949814.

It is an arithmetic number, because the mean of its divisors is an integer number (69648565).

Almost surely, 2^397991780 is an apocalyptic number.

It is an amenable number.

397991780 is an abundant number, since it is smaller than the sum of its proper divisors (437791000).

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

397991780 is a wasteful number, since it uses less digits than its factorization.

397991780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19899598 (or 19899596 counting only the distinct ones).

The product of its (nonzero) digits is 857304, while the sum is 53.

The square root of 397991780 is about 19949.7313265116. The cubic root of 397991780 is about 735.5711727879.

It can be divided in two parts, 3979 and 91780, that added together give a palindrome (95759).

The spelling of 397991780 in words is "three hundred ninety-seven million, nine hundred ninety-one thousand, seven hundred eighty".