21989127 has 8 divisors (see below), whose sum is σ = 30593664. Its totient is φ = 14022008.

The previous prime is 21989119. The next prime is 21989129. The reversal of 21989127 is 72198912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21989127 - 2³ = 21989119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21989129) 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 7 ways as a sum of consecutive naturals, for example, 159273 + ... + 159410.

It is an arithmetic number, because the mean of its divisors is an integer number (3824208).

Almost surely, 2^21989127 is an apocalyptic number.

21989127 is a deficient number, since it is larger than the sum of its proper divisors (8604537).

21989127 is a wasteful number, since it uses less digits than its factorization.

21989127 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 318709.

The product of its digits is 18144, while the sum is 39.

The square root of 21989127 is about 4689.2565508831. The cubic root of 21989127 is about 280.1577639835.

It can be divided in two parts, 2198 and 9127, that added together give a triangular number (11325 = T₁₅₀).

The spelling of 21989127 in words is "twenty-one million, nine hundred eighty-nine thousand, one hundred twenty-seven".