21587234 has 4 divisors (see below), whose sum is σ = 32380854. Its totient is φ = 10793616.

The previous prime is 21587233. The next prime is 21587257. The reversal of 21587234 is 43278512.

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

It can be written as a sum of positive squares in only one way, i.e., 20675209 + 912025 = 4547^2 + 955^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21587234.

It is not an unprimeable number, because it can be changed into a prime (21587233) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5396807 + ... + 5396810.

Almost surely, 2^21587234 is an apocalyptic number.

21587234 is a deficient number, since it is larger than the sum of its proper divisors (10793620).

21587234 is a wasteful number, since it uses less digits than its factorization.

21587234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10793619.

The product of its digits is 13440, while the sum is 32.

The square root of 21587234 is about 4646.2064095346. The cubic root of 21587234 is about 278.4404539053.

The spelling of 21587234 in words is "twenty-one million, five hundred eighty-seven thousand, two hundred thirty-four".