1661518435 has 4 divisors (see below), whose sum is σ = 1993822128. Its totient is φ = 1329214744.

The previous prime is 1661518421. The next prime is 1661518447. The reversal of 1661518435 is 5348151661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5348151661 = 661 ⋅8091001.

It is a cyclic number.

It is not a de Polignac number, because 1661518435 - 2²⁵ = 1627964003 is a prime.

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 Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 166151839 + ... + 166151848.

It is an arithmetic number, because the mean of its divisors is an integer number (498455532).

Almost surely, 2^1661518435 is an apocalyptic number.

1661518435 is a deficient number, since it is larger than the sum of its proper divisors (332303693).

1661518435 is an equidigital number, since it uses as much as digits as its factorization.

1661518435 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 332303692.

The product of its digits is 86400, while the sum is 40.

The square root of 1661518435 is about 40761.7275762449. The cubic root of 1661518435 is about 1184.4090616464.

The spelling of 1661518435 in words is "one billion, six hundred sixty-one million, five hundred eighteen thousand, four hundred thirty-five".