21797453 has 4 divisors (see below), whose sum is σ = 21812700. Its totient is φ = 21782208.

The previous prime is 21797449. The next prime is 21797467. The reversal of 21797453 is 35479712.

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 3247204 + 18550249 = 1802^2 + 4307^2 .

It is a cyclic number.

It is not a de Polignac number, because 21797453 - 2² = 21797449 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 (21797423) 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, 5228 + ... + 8421.

It is an arithmetic number, because the mean of its divisors is an integer number (5453175).

Almost surely, 2^21797453 is an apocalyptic number.

It is an amenable number.

21797453 is a deficient number, since it is larger than the sum of its proper divisors (15247).

21797453 is a wasteful number, since it uses less digits than its factorization.

21797453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15246.

The product of its digits is 52920, while the sum is 38.

The square root of 21797453 is about 4668.7742502717. The cubic root of 21797453 is about 279.3413643407.

The spelling of 21797453 in words is "twenty-one million, seven hundred ninety-seven thousand, four hundred fifty-three".