400720816 has 20 divisors (see below), whose sum is σ = 776927952. Its totient is φ = 200223296.

The previous prime is 400720813. The next prime is 400720819. The reversal of 400720816 is 618027004.

It is an interprime number because it is at equal distance from previous prime (400720813) and next prime (400720819).

It is not an unprimeable number, because it can be changed into a prime (400720813) 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, 18045 + ... + 33571.

Almost surely, 2^400720816 is an apocalyptic number.

It is an amenable number.

400720816 is a deficient number, since it is larger than the sum of its proper divisors (376207136).

400720816 is a wasteful number, since it uses less digits than its factorization.

400720816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17148 (or 17142 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 400720816 is about 20018.0122889362. The cubic root of 400720816 is about 737.2486189502.

The spelling of 400720816 in words is "four hundred million, seven hundred twenty thousand, eight hundred sixteen".