21270918 has 16 divisors (see below), whose sum is σ = 44781120. Its totient is φ = 6717096.

The previous prime is 21270881. The next prime is 21270919. The reversal of 21270918 is 81907212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21270919) 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, 93180 + ... + 93407.

It is an arithmetic number, because the mean of its divisors is an integer number (2798820).

Almost surely, 2^21270918 is an apocalyptic number.

21270918 is an abundant number, since it is smaller than the sum of its proper divisors (23510202).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21270918 is a wasteful number, since it uses less digits than its factorization.

21270918 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186611.

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21270918 is about 4612.0405462225. The cubic root of 21270918 is about 277.0737681863.

The spelling of 21270918 in words is "twenty-one million, two hundred seventy thousand, nine hundred eighteen".