21897601 has 4 divisors (see below), whose sum is σ = 23888304. Its totient is φ = 19906900.

The previous prime is 21897569. The next prime is 21897611. The reversal of 21897601 is 10679812.

It is a happy number.

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 21897601 - 2⁵ = 21897569 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21897611) 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, 995335 + ... + 995356.

It is an arithmetic number, because the mean of its divisors is an integer number (5972076).

Almost surely, 2^21897601 is an apocalyptic number.

It is an amenable number.

21897601 is a deficient number, since it is larger than the sum of its proper divisors (1990703).

21897601 is a wasteful number, since it uses less digits than its factorization.

21897601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1990702.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21897601 is about 4679.4872582367. The cubic root of 21897601 is about 279.7685204203.

The spelling of 21897601 in words is "twenty-one million, eight hundred ninety-seven thousand, six hundred one".