1561072831 has 2 divisors, whose sum is σ = 1561072832. Its totient is φ = 1561072830.

The previous prime is 1561072829. The next prime is 1561072837. The reversal of 1561072831 is 1382701651.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (1382701651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1561072831 - 2¹ = 1561072829 is a prime.

It is a super-2 number, since 2×1561072831² = 4873896767372709122, which contains 22 as substring.

Together with 1561072829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561072837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780536415 + 780536416.

It is an arithmetic number, because the mean of its divisors is an integer number (780536416).

Almost surely, 2^1561072831 is an apocalyptic number.

1561072831 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561072831 is an equidigital number, since it uses as much as digits as its factorization.

1561072831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 1561072831 is about 39510.4142094208. The cubic root of 1561072831 is about 1160.0438030923.

The spelling of 1561072831 in words is "one billion, five hundred sixty-one million, seventy-two thousand, eight hundred thirty-one".