1561920271 has 8 divisors (see below), whose sum is σ = 1725702624. Its totient is φ = 1406127360.

The previous prime is 1561920259. The next prime is 1561920301. The reversal of 1561920271 is 1720291651.

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 1561920271 - 2¹¹ = 1561918223 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 (1561920571) 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, 1996950 + ... + 1997731.

It is an arithmetic number, because the mean of its divisors is an integer number (215712828).

Almost surely, 2^1561920271 is an apocalyptic number.

1561920271 is a deficient number, since it is larger than the sum of its proper divisors (163782353).

1561920271 is a wasteful number, since it uses less digits than its factorization.

1561920271 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3994721.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 1561920271 is about 39521.1370155263. The cubic root of 1561920271 is about 1160.2536779224.

The spelling of 1561920271 in words is "one billion, five hundred sixty-one million, nine hundred twenty thousand, two hundred seventy-one".