21369018 has 32 divisors (see below), whose sum is σ = 46886400. Its totient is φ = 6438960.

The previous prime is 21369011. The next prime is 21369031. The reversal of 21369018 is 81096312.

It is not an unprimeable number, because it can be changed into a prime (21369011) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12321 + ... + 13947.

It is an arithmetic number, because the mean of its divisors is an integer number (1465200).

Almost surely, 2^21369018 is an apocalyptic number.

21369018 is an abundant number, since it is smaller than the sum of its proper divisors (25517382).

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

21369018 is a wasteful number, since it uses less digits than its factorization.

21369018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1842.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21369018 is about 4622.6635179299. The cubic root of 21369018 is about 277.4990633846.

The spelling of 21369018 in words is "twenty-one million, three hundred sixty-nine thousand, eighteen".