139515661 has 4 divisors (see below), whose sum is σ = 142918524. Its totient is φ = 136112800.

The previous prime is 139515637. The next prime is 139515667. The reversal of 139515661 is 166515931.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59752900 + 79762761 = 7730^2 + 8931^2 .

It is a cyclic number.

It is not a de Polignac number, because 139515661 - 2¹¹ = 139513613 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 139515661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (139515667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1701370 + ... + 1701451.

It is an arithmetic number, because the mean of its divisors is an integer number (35729631).

Almost surely, 2^139515661 is an apocalyptic number.

It is an amenable number.

139515661 is a deficient number, since it is larger than the sum of its proper divisors (3402863).

139515661 is an equidigital number, since it uses as much as digits as its factorization.

139515661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3402862.

The product of its digits is 24300, while the sum is 37.

The square root of 139515661 is about 11811.6747754076. The cubic root of 139515661 is about 518.6499260965.

The spelling of 139515661 in words is "one hundred thirty-nine million, five hundred fifteen thousand, six hundred sixty-one".