1561771233401 has 4 divisors (see below), whose sum is σ = 1581540489600. Its totient is φ = 1542001977204.

The previous prime is 1561771233307. The next prime is 1561771233433. The reversal of 1561771233401 is 1043321771651.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1561771233401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561771232401) 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, 9884627981 + ... + 9884628138.

It is an arithmetic number, because the mean of its divisors is an integer number (395385122400).

Almost surely, 2^{1561771233401} is an apocalyptic number.

It is an amenable number.

1561771233401 is a deficient number, since it is larger than the sum of its proper divisors (19769256199).

1561771233401 is an equidigital number, since it uses as much as digits as its factorization.

1561771233401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19769256198.

The product of its (nonzero) digits is 105840, while the sum is 41.

The spelling of 1561771233401 in words is "one trillion, five hundred sixty-one billion, seven hundred seventy-one million, two hundred thirty-three thousand, four hundred one".