1661131263 has 8 divisors (see below), whose sum is σ = 2416190976. Its totient is φ = 1006746200.

The previous prime is 1661131229. The next prime is 1661131289. The reversal of 1661131263 is 3621311661.

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 1661131263 - 2⁸ = 1661131007 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1661131263.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661131363) 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, 25168623 + ... + 25168688.

It is an arithmetic number, because the mean of its divisors is an integer number (302023872).

Almost surely, 2^1661131263 is an apocalyptic number.

1661131263 is a deficient number, since it is larger than the sum of its proper divisors (755059713).

1661131263 is a wasteful number, since it uses less digits than its factorization.

1661131263 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50337325.

The product of its digits is 3888, while the sum is 30.

The square root of 1661131263 is about 40756.9780896474. The cubic root of 1661131263 is about 1184.3170563178.

It can be divided in two parts, 16611 and 31263, that added together give a palindrome (47874).

The spelling of 1661131263 in words is "one billion, six hundred sixty-one million, one hundred thirty-one thousand, two hundred sixty-three".