215973 has 16 divisors (see below), whose sum is σ = 337600. Its totient is φ = 136080.

The previous prime is 215959. The next prime is 215981. The reversal of 215973 is 379512.

It is not a de Polignac number, because 215973 - 2⁶ = 215909 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (215953) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 303 + ... + 723.

It is an arithmetic number, because the mean of its divisors is an integer number (21100).

215973 is a Friedman number, since it can be written as (51+9)^3-27, using all its digits and the basic arithmetic operations.

2²¹⁵⁹⁷³ is an apocalyptic number.

It is an amenable number.

215973 is a deficient number, since it is larger than the sum of its proper divisors (121627).

215973 is a wasteful number, since it uses less digits than its factorization.

215973 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449 (or 443 counting only the distinct ones).

The product of its digits is 1890, while the sum is 27.

The square root of 215973 is about 464.7289532620. The cubic root of 215973 is about 59.9974998958.

Adding to 215973 its sum of digits (27), we get a cube (216000 = 60³).

The spelling of 215973 in words is "two hundred fifteen thousand, nine hundred seventy-three".