21260018 has 16 divisors (see below), whose sum is σ = 34419840. Its totient is φ = 9790416.

The previous prime is 21260011. The next prime is 21260021. The reversal of 21260018 is 81006212.

It is not an unprimeable number, because it can be changed into a prime (21260011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19943 + ... + 20981.

It is an arithmetic number, because the mean of its divisors is an integer number (2151240).

Almost surely, 2^21260018 is an apocalyptic number.

21260018 is a deficient number, since it is larger than the sum of its proper divisors (13159822).

21260018 is a wasteful number, since it uses less digits than its factorization.

21260018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1841.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 21260018 is about 4610.8587052739. The cubic root of 21260018 is about 277.0264325065.

The spelling of 21260018 in words is "twenty-one million, two hundred sixty thousand, eighteen".