21307122 has 12 divisors (see below), whose sum is σ = 46165470. Its totient is φ = 7102368.

The previous prime is 21307109. The next prime is 21307123. The reversal of 21307122 is 22170312.

It can be written as a sum of positive squares in only one way, i.e., 14130081 + 7177041 = 3759^2 + 2679^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1183729 = 21307122 / (2 + 1 + 3 + 0 + 7 + 1 + 2 + 2).

It is a junction number, because it is equal to n+sod(n) for n = 21307095 and 21307104.

It is not an unprimeable number, because it can be changed into a prime (21307123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 591847 + ... + 591882.

Almost surely, 2^21307122 is an apocalyptic number.

21307122 is an abundant number, since it is smaller than the sum of its proper divisors (24858348).

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

21307122 is a wasteful number, since it uses less digits than its factorization.

21307122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183737 (or 1183734 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 18.

The square root of 21307122 is about 4615.9638213487. The cubic root of 21307122 is about 277.2308761669.

Adding to 21307122 its reverse (22170312), we get a palindrome (43477434).

The spelling of 21307122 in words is "twenty-one million, three hundred seven thousand, one hundred twenty-two".