21587442 has 8 divisors (see below), whose sum is σ = 43174896. Its totient is φ = 7195812.

The previous prime is 21587431. The next prime is 21587453. The reversal of 21587442 is 24478512.

It is an interprime number because it is at equal distance from previous prime (21587431) and next prime (21587453).

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

21587442 is an admirable number.

It is an unprimeable number.

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, 1798948 + ... + 1798959.

It is an arithmetic number, because the mean of its divisors is an integer number (5396862).

Almost surely, 2^21587442 is an apocalyptic number.

21587442 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21587442 is a wasteful number, since it uses less digits than its factorization.

21587442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3597912.

The product of its digits is 17920, while the sum is 33.

The square root of 21587442 is about 4646.2287933334. The cubic root of 21587442 is about 278.4413481904.

The spelling of 21587442 in words is "twenty-one million, five hundred eighty-seven thousand, four hundred forty-two".