1561646431 has 8 divisors (see below), whose sum is σ = 1593605664. Its totient is φ = 1529779680.

The previous prime is 1561646419. The next prime is 1561646447. The reversal of 1561646431 is 1346461651.

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 1561646431 - 2⁵ = 1561646399 is a prime.

It is a super-2 number, since 2×1561646431² = 4877479150910075522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561646131) 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, 11521 + ... + 57061.

It is an arithmetic number, because the mean of its divisors is an integer number (199200708).

Almost surely, 2^1561646431 is an apocalyptic number.

1561646431 is a deficient number, since it is larger than the sum of its proper divisors (31959233).

1561646431 is an equidigital number, since it uses as much as digits as its factorization.

1561646431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46241.

The product of its digits is 51840, while the sum is 37.

The square root of 1561646431 is about 39517.6723884391. The cubic root of 1561646431 is about 1160.1858677097.

The spelling of 1561646431 in words is "one billion, five hundred sixty-one million, six hundred forty-six thousand, four hundred thirty-one".