21749386 has 8 divisors (see below), whose sum is σ = 32649984. Its totient is φ = 10866060.

The previous prime is 21749353. The next prime is 21749419. The reversal of 21749386 is 68394712.

It is an interprime number because it is at equal distance from previous prime (21749353) and next prime (21749419).

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 490 + ... + 6613.

It is an arithmetic number, because the mean of its divisors is an integer number (4081248).

Almost surely, 2^21749386 is an apocalyptic number.

21749386 is a deficient number, since it is larger than the sum of its proper divisors (10900598).

21749386 is a wasteful number, since it uses less digits than its factorization.

21749386 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8636.

The product of its digits is 72576, while the sum is 40.

The square root of 21749386 is about 4663.6236983702. The cubic root of 21749386 is about 279.1358818755.

The spelling of 21749386 in words is "twenty-one million, seven hundred forty-nine thousand, three hundred eighty-six".