21871140 has 48 divisors (see below), whose sum is σ = 61447680. Its totient is φ = 5812480.

The previous prime is 21871117. The next prime is 21871141. The reversal of 21871140 is 4117812.

It is a self number, because there is not a number n which added to its sum of digits gives 21871140.

It is not an unprimeable number, because it can be changed into a prime (21871141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28360 + ... + 29120.

It is an arithmetic number, because the mean of its divisors is an integer number (1280160).

Almost surely, 2^21871140 is an apocalyptic number.

21871140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21871140 is an abundant number, since it is smaller than the sum of its proper divisors (39576540).

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

21871140 is a wasteful number, since it uses less digits than its factorization.

21871140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252 (or 1250 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 24.

The square root of 21871140 is about 4676.6590639045. The cubic root of 21871140 is about 279.6557844981.

Adding to 21871140 its reverse (4117812), we get a palindrome (25988952).

The spelling of 21871140 in words is "twenty-one million, eight hundred seventy-one thousand, one hundred forty".