399736995840 has 1280 divisors, whose sum is σ = 1769155597440. Its totient is φ = 84085309440.

The previous prime is 399736995839. The next prime is 399736995841. The reversal of 399736995840 is 48599637993.

399736995840 is a `hidden beast` number, since 3 + 9 + 9 + 7 + 36 + 9 + 9 + 584 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (399736995839) and next prime (399736995841).

It is a tau number, because it is divible by the number of its divisors (1280).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399736995841) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1207664475 + ... + 1207664805.

Almost surely, 2^399736995840 is an apocalyptic number.

399736995840 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399736995840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (884577798720).

399736995840 is an abundant number, since it is smaller than the sum of its proper divisors (1369418601600).

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

399736995840 is an equidigital number, since it uses as much as digits as its factorization.

399736995840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398 (or 361 counting only the distinct ones).

The product of its (nonzero) digits is 396809280, while the sum is 72.

The spelling of 399736995840 in words is "three hundred ninety-nine billion, seven hundred thirty-six million, nine hundred ninety-five thousand, eight hundred forty".