138917864640 has 224 divisors, whose sum is σ = 479256791040. Its totient is φ = 33962803200.

The previous prime is 138917864639. The next prime is 138917864647. The reversal of 138917864640 is 46468719831.

It is a super-2 number, since 2×138917864640² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is not an unprimeable number, because it can be changed into a prime (138917864647) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 442600 + ... + 688280.

Almost surely, 2^138917864640 is an apocalyptic number.

138917864640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 138917864640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239628395520).

138917864640 is an abundant number, since it is smaller than the sum of its proper divisors (340338926400).

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

138917864640 is a wasteful number, since it uses less digits than its factorization.

138917864640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245751 (or 245741 counting only the distinct ones).

The product of its (nonzero) digits is 6967296, while the sum is 57.

The spelling of 138917864640 in words is "one hundred thirty-eight billion, nine hundred seventeen million, eight hundred sixty-four thousand, six hundred forty".