399206442497 has 4 divisors (see below), whose sum is σ = 399207796740. Its totient is φ = 399205088256.

The previous prime is 399206442421. The next prime is 399206442529. The reversal of 399206442497 is 794244602993.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 8430177856 + 390776264641 = 91816^2 + 625121^2 .

It is a cyclic number.

It is not a de Polignac number, because 399206442497 - 2⁸ = 399206442241 is a prime.

It is a super-2 number, since 2×399206442497² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399206442407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26672 + ... + 893937.

It is an arithmetic number, because the mean of its divisors is an integer number (99801949185).

Almost surely, 2^399206442497 is an apocalyptic number.

It is an amenable number.

399206442497 is a deficient number, since it is larger than the sum of its proper divisors (1354243).

399206442497 is an equidigital number, since it uses as much as digits as its factorization.

399206442497 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1354242.

The product of its (nonzero) digits is 23514624, while the sum is 59.

The spelling of 399206442497 in words is "three hundred ninety-nine billion, two hundred six million, four hundred forty-two thousand, four hundred ninety-seven".