400343544124021 has 4 divisors (see below), whose sum is σ = 400391096519200. Its totient is φ = 400295991728844.

The previous prime is 400343544124009. The next prime is 400343544124037. The reversal of 400343544124021 is 120421445343004.

It is a happy number.

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 400343544124021 - 2²⁵ = 400343510569589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400343544124621) 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, 23776184961 + ... + 23776201798.

It is an arithmetic number, because the mean of its divisors is an integer number (100097774129800).

Almost surely, 2^{400343544124021} is an apocalyptic number.

It is an amenable number.

400343544124021 is a deficient number, since it is larger than the sum of its proper divisors (47552395179).

400343544124021 is an equidigital number, since it uses as much as digits as its factorization.

400343544124021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47552395178.

The product of its (nonzero) digits is 184320, while the sum is 37.

Adding to 400343544124021 its reverse (120421445343004), we get a palindrome (520764989467025).

The spelling of 400343544124021 in words is "four hundred trillion, three hundred forty-three billion, five hundred forty-four million, one hundred twenty-four thousand, twenty-one".