21870273 has 16 divisors (see below), whose sum is σ = 31412480. Its totient is φ = 13490064.

The previous prime is 21870271. The next prime is 21870307. The reversal of 21870273 is 37207812.

It is not a de Polignac number, because 21870273 - 2¹ = 21870271 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21870273.

It is not an unprimeable number, because it can be changed into a prime (21870271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2011 + ... + 6912.

It is an arithmetic number, because the mean of its divisors is an integer number (1963280).

Almost surely, 2^21870273 is an apocalyptic number.

It is an amenable number.

21870273 is a deficient number, since it is larger than the sum of its proper divisors (9542207).

21870273 is a wasteful number, since it uses less digits than its factorization.

21870273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8988.

The product of its (nonzero) digits is 4704, while the sum is 30.

The square root of 21870273 is about 4676.5663686085. The cubic root of 21870273 is about 279.6520891448.

The spelling of 21870273 in words is "twenty-one million, eight hundred seventy thousand, two hundred seventy-three".