400997520 has 320 divisors, whose sum is σ = 1722746880. Its totient is φ = 83289600.

The previous prime is 400997503. The next prime is 400997551. The reversal of 400997520 is 25799004.

400997520 is a `hidden beast` number, since 40 + 0 + 9 + 97 + 520 = 666.

It is a super-2 number, since 2×400997520² = 321598022092300800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 165115 + ... + 167525.

It is an arithmetic number, because the mean of its divisors is an integer number (5383584).

Almost surely, 2^400997520 is an apocalyptic number.

400997520 is a gapful number since it is divisible by the number (40) 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 400997520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (861373440).

400997520 is an abundant number, since it is smaller than the sum of its proper divisors (1321749360).

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

400997520 is a wasteful number, since it uses less digits than its factorization.

400997520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2451 (or 2439 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 400997520 is about 20024.9224717600. The cubic root of 400997520 is about 737.4182738127.

The spelling of 400997520 in words is "four hundred million, nine hundred ninety-seven thousand, five hundred twenty".