21018195 has 24 divisors (see below), whose sum is σ = 39744432. Its totient is φ = 10190400.

The previous prime is 21018191. The next prime is 21018211. The reversal of 21018195 is 59181012.

It is not a de Polignac number, because 21018195 - 2² = 21018191 is a prime.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (21018191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20736 + ... + 21725.

It is an arithmetic number, because the mean of its divisors is an integer number (1656018).

Almost surely, 2^21018195 is an apocalyptic number.

21018195 is a deficient number, since it is larger than the sum of its proper divisors (18726237).

21018195 is a wasteful number, since it uses less digits than its factorization.

21018195 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42483 (or 42480 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 21018195 is about 4584.5605023819. The cubic root of 21018195 is about 275.9720749945.

It can be divided in two parts, 210181 and 95, that added together give a triangular number (210276 = T₆₄₈).

The spelling of 21018195 in words is "twenty-one million, eighteen thousand, one hundred ninety-five".