1561612631 has 4 divisors (see below), whose sum is σ = 1611987264. Its totient is φ = 1511238000.

The previous prime is 1561612621. The next prime is 1561612651. The reversal of 1561612631 is 1362161651.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1561612631 - 2⁶ = 1561612567 is a prime.

It is a super-2 number, since 2×1561612631² = 4877268018597484322, 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 (1561612621) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25187270 + ... + 25187331.

It is an arithmetic number, because the mean of its divisors is an integer number (402996816).

Almost surely, 2^1561612631 is an apocalyptic number.

1561612631 is a deficient number, since it is larger than the sum of its proper divisors (50374633).

1561612631 is an equidigital number, since it uses as much as digits as its factorization.

1561612631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50374632.

The product of its digits is 6480, while the sum is 32.

The square root of 1561612631 is about 39517.2447293583. The cubic root of 1561612631 is about 1160.1774973632.

The spelling of 1561612631 in words is "one billion, five hundred sixty-one million, six hundred twelve thousand, six hundred thirty-one".