21935897 has 4 divisors (see below), whose sum is σ = 21989940. Its totient is φ = 21881856.

The previous prime is 21935869. The next prime is 21935909. The reversal of 21935897 is 79853912.

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 12082576 + 9853321 = 3476^2 + 3139^2 .

It is a cyclic number.

It is not a de Polignac number, because 21935897 - 2⁶ = 21935833 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21935297) 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, 26408 + ... + 27225.

It is an arithmetic number, because the mean of its divisors is an integer number (5497485).

Almost surely, 2^21935897 is an apocalyptic number.

It is an amenable number.

21935897 is a deficient number, since it is larger than the sum of its proper divisors (54043).

21935897 is an equidigital number, since it uses as much as digits as its factorization.

21935897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 54042.

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

The square root of 21935897 is about 4683.5773720523. The cubic root of 21935897 is about 279.9315181161.

The spelling of 21935897 in words is "twenty-one million, nine hundred thirty-five thousand, eight hundred ninety-seven".