1722256505661 has 4 divisors (see below), whose sum is σ = 2296342007552. Its totient is φ = 1148171003772.

The previous prime is 1722256505611. The next prime is 1722256505681. The reversal of 1722256505661 is 1665056522271.

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 not a de Polignac number, because 1722256505661 - 2⁶ = 1722256505597 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 1722256505661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1722256505611) 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, 287042750941 + ... + 287042750946.

It is an arithmetic number, because the mean of its divisors is an integer number (574085501888).

Almost surely, 2^{1722256505661} is an apocalyptic number.

It is an amenable number.

1722256505661 is a deficient number, since it is larger than the sum of its proper divisors (574085501891).

1722256505661 is an equidigital number, since it uses as much as digits as its factorization.

1722256505661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574085501890.

The product of its (nonzero) digits is 1512000, while the sum is 48.

The spelling of 1722256505661 in words is "one trillion, seven hundred twenty-two billion, two hundred fifty-six million, five hundred five thousand, six hundred sixty-one".