399273840 has 160 divisors (see below), whose sum is σ = 1571804160. Its totient is φ = 91259136.

The previous prime is 399273839. The next prime is 399273841. The reversal of 399273840 is 48372993.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (399273839) and next prime (399273841).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399273841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1917 + ... + 28323.

It is an arithmetic number, because the mean of its divisors is an integer number (9823776).

Almost surely, 2^399273840 is an apocalyptic number.

399273840 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 399273840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (785902080).

399273840 is an abundant number, since it is smaller than the sum of its proper divisors (1172530320).

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

399273840 is a wasteful number, since it uses less digits than its factorization.

399273840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26436 (or 26424 counting only the distinct ones).

The product of its (nonzero) digits is 326592, while the sum is 45.

The square root of 399273840 is about 19981.8377533199. The cubic root of 399273840 is about 736.3601635950.

The spelling of 399273840 in words is "three hundred ninety-nine million, two hundred seventy-three thousand, eight hundred forty".