21227985 has 24 divisors (see below), whose sum is σ = 38961000. Its totient is φ = 10655232.

The previous prime is 21227977. The next prime is 21227989. The reversal of 21227985 is 58972212.

It can be written as a sum of positive squares in 4 ways, for example, as 2461761 + 18766224 = 1569^2 + 4332^2 .

It is not a de Polignac number, because 21227985 - 2³ = 21227977 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21227989) 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 23 ways as a sum of consecutive naturals, for example, 13110 + ... + 14639.

It is an arithmetic number, because the mean of its divisors is an integer number (1623375).

Almost surely, 2^21227985 is an apocalyptic number.

It is an amenable number.

21227985 is a deficient number, since it is larger than the sum of its proper divisors (17733015).

21227985 is a wasteful number, since it uses less digits than its factorization.

21227985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27777 (or 27774 counting only the distinct ones).

The product of its digits is 20160, while the sum is 36.

The square root of 21227985 is about 4607.3837478552. The cubic root of 21227985 is about 276.8872283545.

The spelling of 21227985 in words is "twenty-one million, two hundred twenty-seven thousand, nine hundred eighty-five".