400129531 has 4 divisors (see below), whose sum is σ = 421189000. Its totient is φ = 379070064.

The previous prime is 400129523. The next prime is 400129567. The reversal of 400129531 is 135921004.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 400129531 - 2³ = 400129523 is a prime.

It is a super-2 number, since 2×400129531² = 320207283156559922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 400129496 and 400129505.

It is not an unprimeable number, because it can be changed into a prime (400129831) 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, 10529706 + ... + 10529743.

It is an arithmetic number, because the mean of its divisors is an integer number (105297250).

Almost surely, 2^400129531 is an apocalyptic number.

400129531 is a deficient number, since it is larger than the sum of its proper divisors (21059469).

400129531 is a wasteful number, since it uses less digits than its factorization.

400129531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21059468.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 400129531 is about 20003.2380128818. The cubic root of 400129531 is about 736.8858238587.

The spelling of 400129531 in words is "four hundred million, one hundred twenty-nine thousand, five hundred thirty-one".