21040989 has 8 divisors (see below), whose sum is σ = 28121472. Its totient is φ = 13993920.

The previous prime is 21040973. The next prime is 21040997. The reversal of 21040989 is 98904012.

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

It is not a de Polignac number, because 21040989 - 2⁴ = 21040973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21040919) 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, 6844 + ... + 9429.

It is an arithmetic number, because the mean of its divisors is an integer number (3515184).

Almost surely, 2^21040989 is an apocalyptic number.

It is an amenable number.

21040989 is a deficient number, since it is larger than the sum of its proper divisors (7080483).

21040989 is a wasteful number, since it uses less digits than its factorization.

21040989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16707.

The product of its (nonzero) digits is 5184, while the sum is 33.

The square root of 21040989 is about 4587.0457813281. The cubic root of 21040989 is about 276.0718018399.

The spelling of 21040989 in words is "twenty-one million, forty thousand, nine hundred eighty-nine".