961721 has 4 divisors (see below), whose sum is σ = 973392. Its totient is φ = 950052.

The previous prime is 961703. The next prime is 961729. The reversal of 961721 is 127169.

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 961721 - 2⁶ = 961657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (961729) 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, 5711 + ... + 5876.

It is an arithmetic number, because the mean of its divisors is an integer number (243348).

2⁹⁶¹⁷²¹ is an apocalyptic number.

It is an amenable number.

961721 is a deficient number, since it is larger than the sum of its proper divisors (11671).

961721 is a wasteful number, since it uses less digits than its factorization.

961721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11670.

The product of its digits is 756, while the sum is 26.

The square root of 961721 is about 980.6737479917. The cubic root of 961721 is about 98.7073971011.

The spelling of 961721 in words is "nine hundred sixty-one thousand, seven hundred twenty-one".