21272140 has 24 divisors (see below), whose sum is σ = 44760240. Its totient is φ = 8491968.

The previous prime is 21272129. The next prime is 21272149. The reversal of 21272140 is 4127212.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (21272149) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15939 + ... + 17221.

It is an arithmetic number, because the mean of its divisors is an integer number (1865010).

Almost surely, 2^21272140 is an apocalyptic number.

21272140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21272140 is an abundant number, since it is smaller than the sum of its proper divisors (23488100).

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

21272140 is a wasteful number, since it uses less digits than its factorization.

21272140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2121 (or 2119 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 19.

The square root of 21272140 is about 4612.1730236408. The cubic root of 21272140 is about 277.0790739856.

Adding to 21272140 its reverse (4127212), we get a palindrome (25399352).

It can be divided in two parts, 21272 and 140, that added together give a palindrome (21412).

The spelling of 21272140 in words is "twenty-one million, two hundred seventy-two thousand, one hundred forty".