3161721 has 8 divisors (see below), whose sum is σ = 4351744. Its totient is φ = 2039760.

The previous prime is 3161707. The next prime is 3161749. The reversal of 3161721 is 1271613.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 3161721 - 2⁵ = 3161689 is a prime.

It is an Ulam number.

It is a Duffinian number.

3161721 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (3161321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16906 + ... + 17091.

It is an arithmetic number, because the mean of its divisors is an integer number (543968).

Almost surely, 2^3161721 is an apocalyptic number.

3161721 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

It is an amenable number.

3161721 is a deficient number, since it is larger than the sum of its proper divisors (1190023).

3161721 is a wasteful number, since it uses less digits than its factorization.

3161721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34031.

The product of its digits is 252, while the sum is 21.

The square root of 3161721 is about 1778.1228866420. The cubic root of 3161721 is about 146.7713136314.

The spelling of 3161721 in words is "three million, one hundred sixty-one thousand, seven hundred twenty-one".