21242277 has 32 divisors (see below), whose sum is σ = 36495360. Its totient is φ = 11959920.

The previous prime is 21242237. The next prime is 21242339. The reversal of 21242277 is 77224212.

It is not a de Polignac number, because 21242277 - 2¹⁶ = 21176741 is a prime.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21242277.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21242237) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12628 + ... + 14210.

It is an arithmetic number, because the mean of its divisors is an integer number (1140480).

Almost surely, 2^21242277 is an apocalyptic number.

21242277 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21242277 is a deficient number, since it is larger than the sum of its proper divisors (15253083).

21242277 is a wasteful number, since it uses less digits than its factorization.

21242277 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1670 (or 1664 counting only the distinct ones).

The product of its digits is 3136, while the sum is 27.

The square root of 21242277 is about 4608.9344755594. The cubic root of 21242277 is about 276.9493536497.

Adding to 21242277 its reverse (77224212), we get a palindrome (98466489).

The spelling of 21242277 in words is "twenty-one million, two hundred forty-two thousand, two hundred seventy-seven".