399156001 has 4 divisors (see below), whose sum is σ = 405699604. Its totient is φ = 392612400.

The previous prime is 399155993. The next prime is 399156019. The reversal of 399156001 is 100651993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 100651993 = 13 ⋅7742461.

It can be written as a sum of positive squares in 2 ways, for example, as 31091776 + 368064225 = 5576^2 + 19185^2 .

It is a cyclic number.

It is not a de Polignac number, because 399156001 - 2³ = 399155993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399156071) 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, 3271710 + ... + 3271831.

It is an arithmetic number, because the mean of its divisors is an integer number (101424901).

Almost surely, 2^399156001 is an apocalyptic number.

It is an amenable number.

399156001 is a deficient number, since it is larger than the sum of its proper divisors (6543603).

399156001 is an equidigital number, since it uses as much as digits as its factorization.

399156001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6543602.

The product of its (nonzero) digits is 7290, while the sum is 34.

The square root of 399156001 is about 19978.8888830185. Note that the first 5 decimals coincide. The cubic root of 399156001 is about 736.2877150026.

The spelling of 399156001 in words is "three hundred ninety-nine million, one hundred fifty-six thousand, one".