135155721 has 32 divisors (see below), whose sum is σ = 196116480. Its totient is φ = 82512000.

The previous prime is 135155717. The next prime is 135155723. The reversal of 135155721 is 127551531.

It is not a de Polignac number, because 135155721 - 2² = 135155717 is a prime.

It is not an unprimeable number, because it can be changed into a prime (135155723) 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, 352696 + ... + 353078.

It is an arithmetic number, because the mean of its divisors is an integer number (6128640).

Almost surely, 2^135155721 is an apocalyptic number.

It is an amenable number.

135155721 is a deficient number, since it is larger than the sum of its proper divisors (60960759).

135155721 is a wasteful number, since it uses less digits than its factorization.

135155721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597.

The product of its digits is 5250, while the sum is 30.

The square root of 135155721 is about 11625.6492721912. The cubic root of 135155721 is about 513.1899520375.

The spelling of 135155721 in words is "one hundred thirty-five million, one hundred fifty-five thousand, seven hundred twenty-one".