399179975840840 has 16 divisors (see below), whose sum is σ = 898154945641980. Its totient is φ = 159671990336320.

The previous prime is 399179975840819. The next prime is 399179975840843. The reversal of 399179975840840 is 48048579971993.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 366423744271204 + 32756231569636 = 19142198^2 + 5723306^2 .

It is a super-2 number, since 2×399179975840840² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (399179975840843) 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, 4989749697971 + ... + 4989749698050.

Almost surely, 2^{399179975840840} is an apocalyptic number.

It is an amenable number.

399179975840840 is an abundant number, since it is smaller than the sum of its proper divisors (498974969801140).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399179975840840 is a wasteful number, since it uses less digits than its factorization.

399179975840840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9979499396032 (or 9979499396028 counting only the distinct ones).

The product of its (nonzero) digits is 4938071040, while the sum is 83.

The spelling of 399179975840840 in words is "three hundred ninety-nine trillion, one hundred seventy-nine billion, nine hundred seventy-five million, eight hundred forty thousand, eight hundred forty".