1561880261 has 8 divisors (see below), whose sum is σ = 1578489984. Its totient is φ = 1545293200.

The previous prime is 1561880249. The next prime is 1561880339. The reversal of 1561880261 is 1620881651.

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

It is a cyclic number.

It is not a de Polignac number, because 1561880261 - 2⁶ = 1561880197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561880461) 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, 157496 + ... + 167118.

It is an arithmetic number, because the mean of its divisors is an integer number (197311248).

Almost surely, 2^1561880261 is an apocalyptic number.

It is an amenable number.

1561880261 is a deficient number, since it is larger than the sum of its proper divisors (16609723).

1561880261 is a wasteful number, since it uses less digits than its factorization.

1561880261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11331.

The product of its (nonzero) digits is 23040, while the sum is 38.

The square root of 1561880261 is about 39520.6308274552. The cubic root of 1561880261 is about 1160.2437708554.

The spelling of 1561880261 in words is "one billion, five hundred sixty-one million, eight hundred eighty thousand, two hundred sixty-one".