399917569 has 8 divisors (see below), whose sum is σ = 415431720. Its totient is φ = 384518400.

The previous prime is 399917561. The next prime is 399917591. The reversal of 399917569 is 965719993.

It can be written as a sum of positive squares in 4 ways, for example, as 240653169 + 159264400 = 15513^2 + 12620^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399917569 - 2³ = 399917561 is a prime.

It is a super-2 number, since 2×399917569² = 319868123989739522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399917561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21622 + ... + 35599.

It is an arithmetic number, because the mean of its divisors is an integer number (51928965).

Almost surely, 2^399917569 is an apocalyptic number.

It is an amenable number.

399917569 is a deficient number, since it is larger than the sum of its proper divisors (15514151).

399917569 is a wasteful number, since it uses less digits than its factorization.

399917569 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57491.

The product of its digits is 4133430, while the sum is 58.

The square root of 399917569 is about 19997.9391188192. The cubic root of 399917569 is about 736.7556831842.

The spelling of 399917569 in words is "three hundred ninety-nine million, nine hundred seventeen thousand, five hundred sixty-nine".