1661635039 has 4 divisors (see below), whose sum is σ = 1696989024. Its totient is φ = 1626281056.

The previous prime is 1661635021. The next prime is 1661635049. The reversal of 1661635039 is 9305361661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9305361661 = 191 ⋅48719171.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1661635039 is a prime.

It is a super-2 number, since 2×1661635039² = 5522062005665063042, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1661634992 and 1661635010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661635009) 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, 17676922 + ... + 17677015.

It is an arithmetic number, because the mean of its divisors is an integer number (424247256).

Almost surely, 2^1661635039 is an apocalyptic number.

1661635039 is a deficient number, since it is larger than the sum of its proper divisors (35353985).

1661635039 is an equidigital number, since it uses as much as digits as its factorization.

1661635039 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35353984.

The product of its (nonzero) digits is 87480, while the sum is 40.

The square root of 1661635039 is about 40763.1578634433. The cubic root of 1661635039 is about 1184.4367679502.

The spelling of 1661635039 in words is "one billion, six hundred sixty-one million, six hundred thirty-five thousand, thirty-nine".