21272355 has 128 divisors (see below), whose sum is σ = 46448640. Its totient is φ = 9123840.

The previous prime is 21272351. The next prime is 21272357. The reversal of 21272355 is 55327212.

It is not a de Polignac number, because 21272355 - 2² = 21272351 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21272351) by changing a digit.

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 in 127 ways as a sum of consecutive naturals, for example, 686190 + ... + 686220.

It is an arithmetic number, because the mean of its divisors is an integer number (362880).

Almost surely, 2^21272355 is an apocalyptic number.

21272355 is an abundant number, since it is smaller than the sum of its proper divisors (25176285).

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

21272355 is a wasteful number, since it uses less digits than its factorization.

21272355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98 (or 92 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 21272355 is about 4612.1963314673. The cubic root of 21272355 is about 277.0800074726.

Adding to 21272355 its reverse (55327212), we get a palindrome (76599567).

The spelling of 21272355 in words is "twenty-one million, two hundred seventy-two thousand, three hundred fifty-five".