1561082638 has 4 divisors (see below), whose sum is σ = 2341623960. Its totient is φ = 780541318.

The previous prime is 1561082587. The next prime is 1561082639. The reversal of 1561082638 is 8362801651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8362801651 = 18839 ⋅443909.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 1561082638.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1561082639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 390270658 + ... + 390270661.

It is an arithmetic number, because the mean of its divisors is an integer number (585405990).

Almost surely, 2^1561082638 is an apocalyptic number.

1561082638 is a deficient number, since it is larger than the sum of its proper divisors (780541322).

1561082638 is an equidigital number, since it uses as much as digits as its factorization.

1561082638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 780541321.

The product of its (nonzero) digits is 69120, while the sum is 40.

The square root of 1561082638 is about 39510.5383157456. The cubic root of 1561082638 is about 1160.0462323032.

The spelling of 1561082638 in words is "one billion, five hundred sixty-one million, eighty-two thousand, six hundred thirty-eight".