21458887 has 4 divisors (see below), whose sum is σ = 21476016. Its totient is φ = 21441760.

The previous prime is 21458821. The next prime is 21458893. The reversal of 21458887 is 78885412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21458887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21458807) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6523 + ... + 9244.

It is an arithmetic number, because the mean of its divisors is an integer number (5369004).

Almost surely, 2^21458887 is an apocalyptic number.

21458887 is a deficient number, since it is larger than the sum of its proper divisors (17129).

21458887 is a wasteful number, since it uses less digits than its factorization.

21458887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17128.

The product of its digits is 143360, while the sum is 43.

The square root of 21458887 is about 4632.3737975254. The cubic root of 21458887 is about 277.8875336526.

The spelling of 21458887 in words is "twenty-one million, four hundred fifty-eight thousand, eight hundred eighty-seven".