400018381820 has 24 divisors (see below), whose sum is σ = 842290731744. Its totient is φ = 159578375616.

The previous prime is 400018381769. The next prime is 400018381837. The reversal of 400018381820 is 28183810004.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26803424 + ... + 26818343.

It is an arithmetic number, because the mean of its divisors is an integer number (35095447156).

Almost surely, 2^400018381820 is an apocalyptic number.

It is an amenable number.

400018381820 is an abundant number, since it is smaller than the sum of its proper divisors (442272349924).

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

400018381820 is a wasteful number, since it uses less digits than its factorization.

400018381820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53622149 (or 53622147 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 35.

The spelling of 400018381820 in words is "four hundred billion, eighteen million, three hundred eighty-one thousand, eight hundred twenty".