1561660139 has 8 divisors (see below), whose sum is σ = 1682107392. Its totient is φ = 1441258560.

The previous prime is 1561660109. The next prime is 1561660151. The reversal of 1561660139 is 9310661651.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561660139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561660109) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 99734 + ... + 114324.

It is an arithmetic number, because the mean of its divisors is an integer number (210263424).

Almost surely, 2^1561660139 is an apocalyptic number.

1561660139 is a deficient number, since it is larger than the sum of its proper divisors (120447253).

1561660139 is a wasteful number, since it uses less digits than its factorization.

1561660139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22837.

The product of its (nonzero) digits is 29160, while the sum is 38.

The square root of 1561660139 is about 39517.8458294477. The cubic root of 1561660139 is about 1160.1892623709.

The spelling of 1561660139 in words is "one billion, five hundred sixty-one million, six hundred sixty thousand, one hundred thirty-nine".