21905097 has 4 divisors (see below), whose sum is σ = 29206800. Its totient is φ = 14603396.

The previous prime is 21905089. The next prime is 21905099. The reversal of 21905097 is 79050912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21905097 - 2³ = 21905089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21905099) 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, 3650847 + ... + 3650852.

It is an arithmetic number, because the mean of its divisors is an integer number (7301700).

Almost surely, 2^21905097 is an apocalyptic number.

It is an amenable number.

21905097 is a deficient number, since it is larger than the sum of its proper divisors (7301703).

21905097 is an equidigital number, since it uses as much as digits as its factorization.

21905097 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7301702.

The product of its (nonzero) digits is 5670, while the sum is 33.

The square root of 21905097 is about 4680.2881321560. The cubic root of 21905097 is about 279.8004402879.

The spelling of 21905097 in words is "twenty-one million, nine hundred five thousand, ninety-seven".