138242640 has 160 divisors (see below), whose sum is σ = 468827136. Its totient is φ = 33546240.

The previous prime is 138242633. The next prime is 138242659. The reversal of 138242640 is 46242831.

It is a super-2 number, since 2×138242640² = 38222055028339200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 138242598 and 138242607.

It is a congruent number.

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, 125934 + ... + 127026.

Almost surely, 2^138242640 is an apocalyptic number.

138242640 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 138242640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (234413568).

138242640 is an abundant number, since it is smaller than the sum of its proper divisors (330584496).

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

138242640 is a wasteful number, since it uses less digits than its factorization.

138242640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1157 (or 1151 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 30.

The square root of 138242640 is about 11757.6630331031. The cubic root of 138242640 is about 517.0676170841.

The spelling of 138242640 in words is "one hundred thirty-eight million, two hundred forty-two thousand, six hundred forty".