161209999921435 has 4 divisors (see below), whose sum is σ = 193451999905728. Its totient is φ = 128967999937144.

The previous prime is 161209999921427. The next prime is 161209999921459. The reversal of 161209999921435 is 534129999902161.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 161209999921435 - 2³ = 161209999921427 is a prime.

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, 16120999992139 + ... + 16120999992148.

It is an arithmetic number, because the mean of its divisors is an integer number (48362999976432).

Almost surely, 2^{161209999921435} is an apocalyptic number.

161209999921435 is a deficient number, since it is larger than the sum of its proper divisors (32241999984293).

161209999921435 is an equidigital number, since it uses as much as digits as its factorization.

161209999921435 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32241999984292.

The product of its (nonzero) digits is 85030560, while the sum is 70.

The spelling of 161209999921435 in words is "one hundred sixty-one trillion, two hundred nine billion, nine hundred ninety-nine million, nine hundred twenty-one thousand, four hundred thirty-five".