21251489 has 8 divisors (see below), whose sum is σ = 24880128. Its totient is φ = 17771040.

The previous prime is 21251467. The next prime is 21251491. The reversal of 21251489 is 98415212.

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

It is not a de Polignac number, because 21251489 - 2¹² = 21247393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21251389) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36737 + ... + 37310.

It is an arithmetic number, because the mean of its divisors is an integer number (3110016).

Almost surely, 2^21251489 is an apocalyptic number.

It is an amenable number.

21251489 is a deficient number, since it is larger than the sum of its proper divisors (3628639).

21251489 is an equidigital number, since it uses as much as digits as its factorization.

21251489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74095.

The product of its digits is 5760, while the sum is 32.

The square root of 21251489 is about 4609.9337305432. The cubic root of 21251489 is about 276.9893821385.

The spelling of 21251489 in words is "twenty-one million, two hundred fifty-one thousand, four hundred eighty-nine".