21243494 has 32 divisors (see below), whose sum is σ = 34497792. Its totient is φ = 9792000.

The previous prime is 21243473. The next prime is 21243503. The reversal of 21243494 is 49434212.

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 154994 + ... + 155130.

It is an arithmetic number, because the mean of its divisors is an integer number (1078056).

Almost surely, 2^21243494 is an apocalyptic number.

21243494 is a deficient number, since it is larger than the sum of its proper divisors (13254298).

21243494 is a wasteful number, since it uses less digits than its factorization.

21243494 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272.

The product of its digits is 6912, while the sum is 29.

The square root of 21243494 is about 4609.0664998457. The cubic root of 21243494 is about 276.9546424884.

The spelling of 21243494 in words is "twenty-one million, two hundred forty-three thousand, four hundred ninety-four".