137021640 has 128 divisors (see below), whose sum is σ = 479520000. Its totient is φ = 31309824.

The previous prime is 137021639. The next prime is 137021669. The reversal of 137021640 is 46120731.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 137021640.

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, 39496 + ... + 42824.

It is an arithmetic number, because the mean of its divisors is an integer number (3746250).

Almost surely, 2^137021640 is an apocalyptic number.

137021640 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 137021640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (239760000).

137021640 is an abundant number, since it is smaller than the sum of its proper divisors (342498360).

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

137021640 is a wasteful number, since it uses less digits than its factorization.

137021640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3364 (or 3346 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 24.

The square root of 137021640 is about 11705.6242892039. The cubic root of 137021640 is about 515.5408149796.

Subtracting from 137021640 its reverse (46120731), we obtain a palindrome (90900909).

The spelling of 137021640 in words is "one hundred thirty-seven million, twenty-one thousand, six hundred forty".