21987834 has 32 divisors (see below), whose sum is σ = 50798016. Its totient is φ = 6270720.

The previous prime is 21987827. The next prime is 21987841. The reversal of 21987834 is 43878912.

It is an interprime number because it is at equal distance from previous prime (21987827) and next prime (21987841).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8677 + ... + 10920.

It is an arithmetic number, because the mean of its divisors is an integer number (1587438).

Almost surely, 2^21987834 is an apocalyptic number.

21987834 is an abundant number, since it is smaller than the sum of its proper divisors (28810182).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21987834 is a wasteful number, since it uses less digits than its factorization.

21987834 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19630.

The product of its digits is 96768, while the sum is 42.

The square root of 21987834 is about 4689.1186805198. The cubic root of 21987834 is about 280.1522726166.

It can be divided in two parts, 219878 and 34, that added together give a palindrome (219912).

The spelling of 21987834 in words is "twenty-one million, nine hundred eighty-seven thousand, eight hundred thirty-four".