21953789 has 8 divisors (see below), whose sum is σ = 25792032. Its totient is φ = 18422640.

The previous prime is 21953777. The next prime is 21953791. The reversal of 21953789 is 98735912.

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

It is a cyclic number.

It is not a de Polignac number, because 21953789 - 2²⁴ = 5176573 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 (21953489) 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, 76619 + ... + 76904.

It is an arithmetic number, because the mean of its divisors is an integer number (3224004).

Almost surely, 2^21953789 is an apocalyptic number.

It is an amenable number.

21953789 is a deficient number, since it is larger than the sum of its proper divisors (3838243).

21953789 is a wasteful number, since it uses less digits than its factorization.

21953789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153547.

The product of its digits is 136080, while the sum is 44.

The square root of 21953789 is about 4685.4870611282. The cubic root of 21953789 is about 280.0076060859.

The spelling of 21953789 in words is "twenty-one million, nine hundred fifty-three thousand, seven hundred eighty-nine".