401691223878 has 32 divisors (see below), whose sum is σ = 966475127040. Its totient is φ = 108728451360.

The previous prime is 401691223861. The next prime is 401691223889. The reversal of 401691223878 is 878322196104.

It is a happy number.

It is a super-2 number, since 2×401691223878² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 401691223878.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 251685433 + ... + 251687028.

It is an arithmetic number, because the mean of its divisors is an integer number (30202347720).

Almost surely, 2^401691223878 is an apocalyptic number.

401691223878 is an abundant number, since it is smaller than the sum of its proper divisors (564783903162).

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

401691223878 is a wasteful number, since it uses less digits than its factorization.

401691223878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503372492.

The product of its (nonzero) digits is 1161216, while the sum is 51.

The spelling of 401691223878 in words is "four hundred one billion, six hundred ninety-one million, two hundred twenty-three thousand, eight hundred seventy-eight".