97921 has 4 divisors (see below), whose sum is σ = 98644. Its totient is φ = 97200.

The previous prime is 97919. The next prime is 97927. The reversal of 97921 is 12979.

97921 = T₂₅₄ + T₂₅₅ + T₂₅₆.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 14400 + 83521 = 120^2 + 289^2 .

It is a 3-Lehmer number, since φ(97921) divides (97921-1)³.

It is a cyclic number.

It is not a de Polignac number, because 97921 - 2¹ = 97919 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 97921.

It is not an unprimeable number, because it can be changed into a prime (97927) 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, 90 + ... + 451.

It is an arithmetic number, because the mean of its divisors is an integer number (24661).

2⁹⁷⁹²¹ is an apocalyptic number.

97921 is the 181-st octagonal number.

97921 is the 256-th centered triangular number.

It is an amenable number.

97921 is a deficient number, since it is larger than the sum of its proper divisors (723).

97921 is a wasteful number, since it uses less digits than its factorization.

97921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 722.

The product of its digits is 1134, while the sum is 28.

The square root of 97921 is about 312.9233132894. The cubic root of 97921 is about 46.0919710029.

It can be divided in two parts, 979 and 21, that added together give a cube (1000 = 10³).

The spelling of 97921 in words is "ninety-seven thousand, nine hundred twenty-one".