1613511881 has 4 divisors (see below), whose sum is σ = 1640859600. Its totient is φ = 1586164164.

The previous prime is 1613511869. The next prime is 1613511917. The reversal of 1613511881 is 1881153161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1881153161 = 149 ⋅12625189.

It is a cyclic number.

It is not a de Polignac number, because 1613511881 - 2¹⁴ = 1613495497 is a prime.

It is a super-2 number, since 2×1613511881² = 5206841180256316322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1613511811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13673771 + ... + 13673888.

It is an arithmetic number, because the mean of its divisors is an integer number (410214900).

Almost surely, 2^1613511881 is an apocalyptic number.

It is an amenable number.

1613511881 is a deficient number, since it is larger than the sum of its proper divisors (27347719).

1613511881 is an equidigital number, since it uses as much as digits as its factorization.

1613511881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27347718.

The product of its digits is 5760, while the sum is 35.

The square root of 1613511881 is about 40168.5434264176. The cubic root of 1613511881 is about 1172.8902854343.

The spelling of 1613511881 in words is "one billion, six hundred thirteen million, five hundred eleven thousand, eight hundred eighty-one".