21454493 has 12 divisors (see below), whose sum is σ = 23183412. Its totient is φ = 19845120.

The previous prime is 21454483. The next prime is 21454541. The reversal of 21454493 is 39445412.

It can be written as a sum of positive squares in 6 ways, for example, as 174724 + 21279769 = 418^2 + 4613^2 .

It is not a de Polignac number, because 21454493 - 2¹⁰ = 21453469 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 (21454483) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17021 + ... + 18237.

It is an arithmetic number, because the mean of its divisors is an integer number (1931951).

Almost surely, 2^21454493 is an apocalyptic number.

It is an amenable number.

21454493 is a deficient number, since it is larger than the sum of its proper divisors (1728919).

21454493 is a wasteful number, since it uses less digits than its factorization.

21454493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1312 (or 1295 counting only the distinct ones).

The product of its digits is 17280, while the sum is 32.

The square root of 21454493 is about 4631.8995023640. The cubic root of 21454493 is about 277.8685652694.

Adding to 21454493 its sum of digits (32), we get a triangular number (21454525 = T₆₅₅₀).

The spelling of 21454493 in words is "twenty-one million, four hundred fifty-four thousand, four hundred ninety-three".