400128621881 has 4 divisors (see below), whose sum is σ = 403007245200. Its totient is φ = 397249998564.

The previous prime is 400128621877. The next prime is 400128621929. The reversal of 400128621881 is 188126821004.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 400128621881 - 2² = 400128621877 is a prime.

It is a super-2 number, since 2×400128621881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400128621281) 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, 1439311451 + ... + 1439311728.

It is an arithmetic number, because the mean of its divisors is an integer number (100751811300).

Almost surely, 2^400128621881 is an apocalyptic number.

It is an amenable number.

400128621881 is a deficient number, since it is larger than the sum of its proper divisors (2878623319).

400128621881 is a wasteful number, since it uses less digits than its factorization.

400128621881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2878623318.

The product of its (nonzero) digits is 49152, while the sum is 41.

The spelling of 400128621881 in words is "four hundred billion, one hundred twenty-eight million, six hundred twenty-one thousand, eight hundred eighty-one".