21434687 has 4 divisors (see below), whose sum is σ = 21736656. Its totient is φ = 21132720.

The previous prime is 21434681. The next prime is 21434719. The reversal of 21434687 is 78643412.

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

It is a cyclic number.

It is not a de Polignac number, because 21434687 - 2²² = 17240383 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 (21434681) 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 3 ways as a sum of consecutive naturals, for example, 150878 + ... + 151019.

It is an arithmetic number, because the mean of its divisors is an integer number (5434164).

Almost surely, 2^21434687 is an apocalyptic number.

21434687 is a deficient number, since it is larger than the sum of its proper divisors (301969).

21434687 is an equidigital number, since it uses as much as digits as its factorization.

21434687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301968.

The product of its digits is 32256, while the sum is 35.

The square root of 21434687 is about 4629.7610089507. The cubic root of 21434687 is about 277.7830329258.

The spelling of 21434687 in words is "twenty-one million, four hundred thirty-four thousand, six hundred eighty-seven".