21642794 has 4 divisors (see below), whose sum is σ = 32464194. Its totient is φ = 10821396.

The previous prime is 21642791. The next prime is 21642799. The reversal of 21642794 is 49724612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 21298225 + 344569 = 4615^2 + 587^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21642791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5410697 + ... + 5410700.

Almost surely, 2^21642794 is an apocalyptic number.

21642794 is a deficient number, since it is larger than the sum of its proper divisors (10821400).

21642794 is a wasteful number, since it uses less digits than its factorization.

21642794 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10821399.

The product of its digits is 24192, while the sum is 35.

The square root of 21642794 is about 4652.1816387583. The cubic root of 21642794 is about 278.6791273499.

The spelling of 21642794 in words is "twenty-one million, six hundred forty-two thousand, seven hundred ninety-four".