401687556138 has 64 divisors (see below), whose sum is σ = 974858250240. Its totient is φ = 121589722800.

The previous prime is 401687556121. The next prime is 401687556157. The reversal of 401687556138 is 831655786104.

It is a happy number.

401687556138 is a `hidden beast` number, since 4 + 0 + 1 + 6 + 8 + 75 + 561 + 3 + 8 = 666.

It is a super-2 number, since 2×401687556138² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 169981 + ... + 912287.

It is an arithmetic number, because the mean of its divisors is an integer number (15232160160).

Almost surely, 2^401687556138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 401687556138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (487429125120).

401687556138 is an abundant number, since it is smaller than the sum of its proper divisors (573170694102).

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

401687556138 is a wasteful number, since it uses less digits than its factorization.

401687556138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 743240 (or 743234 counting only the distinct ones).

The product of its (nonzero) digits is 4838400, while the sum is 54.

The spelling of 401687556138 in words is "four hundred one billion, six hundred eighty-seven million, five hundred fifty-six thousand, one hundred thirty-eight".