21645453 has 8 divisors (see below), whose sum is σ = 29158528. Its totient is φ = 14281344.

The previous prime is 21645451. The next prime is 21645473. The reversal of 21645453 is 35454612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21645453 - 2¹ = 21645451 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21645453.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21645451) 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, 36901 + ... + 37482.

It is an arithmetic number, because the mean of its divisors is an integer number (3644816).

Almost surely, 2^21645453 is an apocalyptic number.

It is an amenable number.

21645453 is a deficient number, since it is larger than the sum of its proper divisors (7513075).

21645453 is an equidigital number, since it uses as much as digits as its factorization.

21645453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74483.

The product of its digits is 14400, while the sum is 30.

The square root of 21645453 is about 4652.4674098805. The cubic root of 21645453 is about 278.6905395773.

The spelling of 21645453 in words is "twenty-one million, six hundred forty-five thousand, four hundred fifty-three".