21887109 has 12 divisors (see below), whose sum is σ = 33474636. Its totient is φ = 13732992.

The previous prime is 21887081. The next prime is 21887119. The reversal of 21887109 is 90178812.

It can be written as a sum of positive squares in 2 ways, for example, as 20223009 + 1664100 = 4497^2 + 1290^2 .

It is not a de Polignac number, because 21887109 - 2¹² = 21883013 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21887119) 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 11 ways as a sum of consecutive naturals, for example, 71374 + ... + 71679.

It is an arithmetic number, because the mean of its divisors is an integer number (2789553).

Almost surely, 2^21887109 is an apocalyptic number.

It is an amenable number.

21887109 is a deficient number, since it is larger than the sum of its proper divisors (11587527).

21887109 is a wasteful number, since it uses less digits than its factorization.

21887109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143076 (or 143073 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 21887109 is about 4678.3660609234. The cubic root of 21887109 is about 279.7238305895.

The spelling of 21887109 in words is "twenty-one million, eight hundred eighty-seven thousand, one hundred nine".