21871055 has 8 divisors (see below), whose sum is σ = 26343744. Its totient is φ = 17431200.

The previous prime is 21871049. The next prime is 21871067. The reversal of 21871055 is 55017812.

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

It is not a de Polignac number, because 21871055 - 2⁴ = 21871039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6716 + ... + 9425.

It is an arithmetic number, because the mean of its divisors is an integer number (3292968).

Almost surely, 2^21871055 is an apocalyptic number.

21871055 is a deficient number, since it is larger than the sum of its proper divisors (4472689).

21871055 is a wasteful number, since it uses less digits than its factorization.

21871055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16417.

The product of its (nonzero) digits is 2800, while the sum is 29.

The square root of 21871055 is about 4676.6499762116. The cubic root of 21871055 is about 279.6554222129.

Adding to 21871055 its reverse (55017812), we get a palindrome (76888867).

The spelling of 21871055 in words is "twenty-one million, eight hundred seventy-one thousand, fifty-five".