21018370 has 16 divisors (see below), whose sum is σ = 39824640. Its totient is φ = 7964784.

The previous prime is 21018323. The next prime is 21018397. The reversal of 21018370 is 7381012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55122 + ... + 55501.

It is an arithmetic number, because the mean of its divisors is an integer number (2489040).

Almost surely, 2^21018370 is an apocalyptic number.

21018370 is a deficient number, since it is larger than the sum of its proper divisors (18806270).

21018370 is a wasteful number, since it uses less digits than its factorization.

21018370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110649.

The product of its (nonzero) digits is 336, while the sum is 22.

The square root of 21018370 is about 4584.5795881411. The cubic root of 21018370 is about 275.9728409178.

Adding to 21018370 its reverse (7381012), we get a palindrome (28399382).

The spelling of 21018370 in words is "twenty-one million, eighteen thousand, three hundred seventy".