21047889 has 8 divisors (see below), whose sum is σ = 28252800. Its totient is φ = 13937456.

The previous prime is 21047861. The next prime is 21047893. The reversal of 21047889 is 98874012.

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 21047889 - 2¹² = 21043793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21047899) 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, 23097 + ... + 23990.

It is an arithmetic number, because the mean of its divisors is an integer number (3531600).

Almost surely, 2^21047889 is an apocalyptic number.

It is an amenable number.

21047889 is a deficient number, since it is larger than the sum of its proper divisors (7204911).

21047889 is a wasteful number, since it uses less digits than its factorization.

21047889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47239.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 21047889 is about 4587.7978377431. The cubic root of 21047889 is about 276.1019760750.

The spelling of 21047889 in words is "twenty-one million, forty-seven thousand, eight hundred eighty-nine".