400509799 has 4 divisors (see below), whose sum is σ = 404638864. Its totient is φ = 396380736.

The previous prime is 400509763. The next prime is 400509803. The reversal of 400509799 is 997905004.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400509799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400509199) 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, 2064387 + ... + 2064580.

It is an arithmetic number, because the mean of its divisors is an integer number (101159716).

Almost surely, 2^400509799 is an apocalyptic number.

400509799 is a deficient number, since it is larger than the sum of its proper divisors (4129065).

400509799 is an equidigital number, since it uses as much as digits as its factorization.

400509799 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4129064.

The product of its (nonzero) digits is 102060, while the sum is 43.

The square root of 400509799 is about 20012.7409167260. The cubic root of 400509799 is about 737.1191861037.

The spelling of 400509799 in words is "four hundred million, five hundred nine thousand, seven hundred ninety-nine".