21247394 has 8 divisors (see below), whose sum is σ = 36424128. Its totient is φ = 9106020.

The previous prime is 21247393. The next prime is 21247411. The reversal of 21247394 is 49374212.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21247394.

It is not an unprimeable number, because it can be changed into a prime (21247393) 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, 758822 + ... + 758849.

It is an arithmetic number, because the mean of its divisors is an integer number (4553016).

Almost surely, 2^21247394 is an apocalyptic number.

21247394 is a deficient number, since it is larger than the sum of its proper divisors (15176734).

21247394 is a wasteful number, since it uses less digits than its factorization.

21247394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1517680.

The product of its digits is 12096, while the sum is 32.

The square root of 21247394 is about 4609.4895595933. The cubic root of 21247394 is about 276.9715897478.

The spelling of 21247394 in words is "twenty-one million, two hundred forty-seven thousand, three hundred ninety-four".