21087634 has 8 divisors (see below), whose sum is σ = 31652208. Its totient is φ = 10536900.

The previous prime is 21087623. The next prime is 21087637. The reversal of 21087634 is 43678012.

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

It is a junction number, because it is equal to n+sod(n) for n = 21087596 and 21087605.

It is not an unprimeable number, because it can be changed into a prime (21087637) 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, 2209 + ... + 6859.

It is an arithmetic number, because the mean of its divisors is an integer number (3956526).

Almost surely, 2^21087634 is an apocalyptic number.

21087634 is a deficient number, since it is larger than the sum of its proper divisors (10564574).

21087634 is a wasteful number, since it uses less digits than its factorization.

21087634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6920.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 21087634 is about 4592.1273937033. The cubic root of 21087634 is about 276.2756557733.

The spelling of 21087634 in words is "twenty-one million, eighty-seven thousand, six hundred thirty-four".