1561956169 has 8 divisors (see below), whose sum is σ = 1578058560. Its totient is φ = 1545872016.

The previous prime is 1561956127. The next prime is 1561956181. The reversal of 1561956169 is 9616591651.

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-1561956169 is a prime.

It is a super-2 number, since 2×1561956169² = 4879414147754313122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561956469) 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, 227022 + ... + 233800.

It is an arithmetic number, because the mean of its divisors is an integer number (197257320).

Almost surely, 2^1561956169 is an apocalyptic number.

It is an amenable number.

1561956169 is a deficient number, since it is larger than the sum of its proper divisors (16102391).

1561956169 is a wasteful number, since it uses less digits than its factorization.

1561956169 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9119.

The product of its digits is 437400, while the sum is 49.

The square root of 1561956169 is about 39521.5911749514. The cubic root of 1561956169 is about 1160.2625666534.

The spelling of 1561956169 in words is "one billion, five hundred sixty-one million, nine hundred fifty-six thousand, one hundred sixty-nine".