139528809 has 24 divisors (see below), whose sum is σ = 243884160. Its totient is φ = 75040128.

The previous prime is 139528801. The next prime is 139528817. The reversal of 139528809 is 908825931.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (139528801) and next prime (139528817).

It is not a de Polignac number, because 139528809 - 2³ = 139528801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (139528801) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 64069 + ... + 66210.

It is an arithmetic number, because the mean of its divisors is an integer number (10161840).

Almost surely, 2^139528809 is an apocalyptic number.

It is an amenable number.

139528809 is a deficient number, since it is larger than the sum of its proper divisors (104355351).

139528809 is a wasteful number, since it uses less digits than its factorization.

139528809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130309 (or 130306 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 139528809 is about 11812.2313302780. The cubic root of 139528809 is about 518.6662181624. Note that the first 3 decimals are identical.

The spelling of 139528809 in words is "one hundred thirty-nine million, five hundred twenty-eight thousand, eight hundred nine".