21958373 has 4 divisors (see below), whose sum is σ = 23250060. Its totient is φ = 20666688.

The previous prime is 21958369. The next prime is 21958381. The reversal of 21958373 is 37385912.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17825284 + 4133089 = 4222^2 + 2033^2 .

It is a cyclic number.

It is not a de Polignac number, because 21958373 - 2² = 21958369 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21958303) 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, 645818 + ... + 645851.

It is an arithmetic number, because the mean of its divisors is an integer number (5812515).

Almost surely, 2^21958373 is an apocalyptic number.

It is an amenable number.

21958373 is a deficient number, since it is larger than the sum of its proper divisors (1291687).

21958373 is a wasteful number, since it uses less digits than its factorization.

21958373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1291686.

The product of its digits is 45360, while the sum is 38.

The square root of 21958373 is about 4685.9762056588. The cubic root of 21958373 is about 280.0270934667.

The spelling of 21958373 in words is "twenty-one million, nine hundred fifty-eight thousand, three hundred seventy-three".