1561642231 has 8 divisors (see below), whose sum is σ = 1607278464. Its totient is φ = 1516662840.

The previous prime is 1561642183. The next prime is 1561642249. The reversal of 1561642231 is 1322461651.

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 not a de Polignac number, because 1561642231 - 2¹¹ = 1561640183 is a prime.

It is a super-2 number, since 2×1561642231² = 4877452915285314722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1561642193 and 1561642202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561645231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 159385 + ... + 168898.

It is an arithmetic number, because the mean of its divisors is an integer number (200909808).

Almost surely, 2^1561642231 is an apocalyptic number.

1561642231 is a deficient number, since it is larger than the sum of its proper divisors (45636233).

1561642231 is an equidigital number, since it uses as much as digits as its factorization.

1561642231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328421.

The product of its digits is 8640, while the sum is 31.

The square root of 1561642231 is about 39517.6192476217. The cubic root of 1561642231 is about 1160.1848276141.

The spelling of 1561642231 in words is "one billion, five hundred sixty-one million, six hundred forty-two thousand, two hundred thirty-one".