21386242 has 8 divisors (see below), whose sum is σ = 32684796. Its totient is φ = 10491312.

The previous prime is 21386237. The next prime is 21386243. The reversal of 21386242 is 24268312.

It can be written as a sum of positive squares in 2 ways, for example, as 20061441 + 1324801 = 4479^2 + 1151^2 .

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 21386242.

It is not an unprimeable number, because it can be changed into a prime (21386243) 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, 100773 + ... + 100984.

Almost surely, 2^21386242 is an apocalyptic number.

21386242 is a deficient number, since it is larger than the sum of its proper divisors (11298554).

21386242 is a wasteful number, since it uses less digits than its factorization.

21386242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201812.

The product of its digits is 4608, while the sum is 28.

The square root of 21386242 is about 4624.5261378870. The cubic root of 21386242 is about 277.5736005840.

The spelling of 21386242 in words is "twenty-one million, three hundred eighty-six thousand, two hundred forty-two".