398787840 has 288 divisors, whose sum is σ = 1545264000. Its totient is φ = 96583680.

The previous prime is 398787839. The next prime is 398787889. The reversal of 398787840 is 48787893.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 379636 + ... + 380684.

It is an arithmetic number, because the mean of its divisors is an integer number (5365500).

Almost surely, 2^398787840 is an apocalyptic number.

398787840 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 398787840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (772632000).

398787840 is an abundant number, since it is smaller than the sum of its proper divisors (1146476160).

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

398787840 is a wasteful number, since it uses less digits than its factorization.

398787840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1090 (or 1070 counting only the distinct ones).

The product of its (nonzero) digits is 2709504, while the sum is 54.

The square root of 398787840 is about 19969.6730068371. The cubic root of 398787840 is about 736.0612740417.

The spelling of 398787840 in words is "three hundred ninety-eight million, seven hundred eighty-seven thousand, eight hundred forty".