21897793 has 8 divisors (see below), whose sum is σ = 22492448. Its totient is φ = 21307104.

The previous prime is 21897781. The next prime is 21897797. The reversal of 21897793 is 39779812.

It is a happy number.

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 21897793 - 2¹³ = 21889601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21897797) 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, 12646 + ... + 14272.

It is an arithmetic number, because the mean of its divisors is an integer number (2811556).

Almost surely, 2^21897793 is an apocalyptic number.

It is an amenable number.

21897793 is a deficient number, since it is larger than the sum of its proper divisors (594655).

21897793 is a wasteful number, since it uses less digits than its factorization.

21897793 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1983.

The product of its digits is 190512, while the sum is 46.

The square root of 21897793 is about 4679.5077732599. The cubic root of 21897793 is about 279.7693380959.

The spelling of 21897793 in words is "twenty-one million, eight hundred ninety-seven thousand, seven hundred ninety-three".