21745982 has 4 divisors (see below), whose sum is σ = 32618976. Its totient is φ = 10872990.

The previous prime is 21745981. The next prime is 21745987. The reversal of 21745982 is 28954712.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21745981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5436494 + ... + 5436497.

It is an arithmetic number, because the mean of its divisors is an integer number (8154744).

Almost surely, 2^21745982 is an apocalyptic number.

21745982 is a deficient number, since it is larger than the sum of its proper divisors (10872994).

21745982 is a wasteful number, since it uses less digits than its factorization.

21745982 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10872993.

The product of its digits is 40320, while the sum is 38.

The square root of 21745982 is about 4663.2587318312. The cubic root of 21745982 is about 279.1213185814.

The spelling of 21745982 in words is "twenty-one million, seven hundred forty-five thousand, nine hundred eighty-two".