21087574 has 4 divisors (see below), whose sum is σ = 31631364. Its totient is φ = 10543786.

The previous prime is 21087569. The next prime is 21087581. The reversal of 21087574 is 47578012.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5271892 + ... + 5271895.

It is an arithmetic number, because the mean of its divisors is an integer number (7907841).

Almost surely, 2^21087574 is an apocalyptic number.

21087574 is a deficient number, since it is larger than the sum of its proper divisors (10543790).

21087574 is a wasteful number, since it uses less digits than its factorization.

21087574 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10543789.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 21087574 is about 4592.1208607788. The cubic root of 21087574 is about 276.2753937468.

The spelling of 21087574 in words is "twenty-one million, eighty-seven thousand, five hundred seventy-four".