1601171631721 has 4 divisors (see below), whose sum is σ = 1608225251472. Its totient is φ = 1594118011972.

The previous prime is 1601171631613. The next prime is 1601171631751. The reversal of 1601171631721 is 1271361711061.

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 not a de Polignac number, because 1601171631721 - 2³⁹ = 1051415817833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1601171631751) 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, 3526809535 + ... + 3526809988.

It is an arithmetic number, because the mean of its divisors is an integer number (402056312868).

Almost surely, 2^{1601171631721} is an apocalyptic number.

It is an amenable number.

1601171631721 is a deficient number, since it is larger than the sum of its proper divisors (7053619751).

1601171631721 is an equidigital number, since it uses as much as digits as its factorization.

1601171631721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7053619750.

The product of its (nonzero) digits is 10584, while the sum is 37.

The spelling of 1601171631721 in words is "one trillion, six hundred one billion, one hundred seventy-one million, six hundred thirty-one thousand, seven hundred twenty-one".