161306440651 has 4 divisors (see below), whose sum is σ = 161307272632. Its totient is φ = 161305608672.

The previous prime is 161306440649. The next prime is 161306440657. The reversal of 161306440651 is 156044603161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 156044603161 = 36683 ⋅4253867.

It is a cyclic number.

It is not a de Polignac number, because 161306440651 - 2¹ = 161306440649 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161306440651.

It is not an unprimeable number, because it can be changed into a prime (161306440657) 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, 45460 + ... + 569806.

It is an arithmetic number, because the mean of its divisors is an integer number (40326818158).

Almost surely, 2^161306440651 is an apocalyptic number.

161306440651 is a deficient number, since it is larger than the sum of its proper divisors (831981).

161306440651 is an equidigital number, since it uses as much as digits as its factorization.

161306440651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 831980.

The product of its (nonzero) digits is 51840, while the sum is 37.

The spelling of 161306440651 in words is "one hundred sixty-one billion, three hundred six million, four hundred forty thousand, six hundred fifty-one".