136721520 has 240 divisors, whose sum is σ = 513737952. Its totient is φ = 33592320.

The previous prime is 136721513. The next prime is 136721537. The reversal of 136721520 is 25127631.

It is a happy number.

136721520 is a `hidden beast` number, since 136 + 7 + 2 + 1 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×136721520² = 37385548062220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 252450 + ... + 252990.

Almost surely, 2^136721520 is an apocalyptic number.

136721520 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 136721520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (256868976).

136721520 is an abundant number, since it is smaller than the sum of its proper divisors (377016432).

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

136721520 is a wasteful number, since it uses less digits than its factorization.

136721520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 582 (or 564 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 27.

The square root of 136721520 is about 11692.7977832510. The cubic root of 136721520 is about 515.1641416024.

The spelling of 136721520 in words is "one hundred thirty-six million, seven hundred twenty-one thousand, five hundred twenty".