398740660 has 12 divisors (see below), whose sum is σ = 837355428. Its totient is φ = 159496256.

The previous prime is 398740649. The next prime is 398740663. The reversal of 398740660 is 66047893.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 245674276 + 153066384 = 15674^2 + 12372^2 .

It is a super-2 number, since 2×398740660² = 317988227874471200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (398740663) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9968497 + ... + 9968536.

It is an arithmetic number, because the mean of its divisors is an integer number (69779619).

Almost surely, 2^398740660 is an apocalyptic number.

It is an amenable number.

398740660 is an abundant number, since it is smaller than the sum of its proper divisors (438614768).

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

398740660 is a wasteful number, since it uses less digits than its factorization.

398740660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19937042 (or 19937040 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 43.

The square root of 398740660 is about 19968.4916806453. The cubic root of 398740660 is about 736.0322454563.

The spelling of 398740660 in words is "three hundred ninety-eight million, seven hundred forty thousand, six hundred sixty".