21420122 has 16 divisors (see below), whose sum is σ = 33265512. Its totient is φ = 10337280.

The previous prime is 21420121. The next prime is 21420131. The reversal of 21420122 is 22102412.

It can be written as a sum of positive squares in 4 ways, for example, as 11566801 + 9853321 = 3401^2 + 3139^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21420097 and 21420106.

It is not an unprimeable number, because it can be changed into a prime (21420121) 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, 6608 + ... + 9300.

Almost surely, 2^21420122 is an apocalyptic number.

21420122 is a deficient number, since it is larger than the sum of its proper divisors (11845390).

21420122 is a wasteful number, since it uses less digits than its factorization.

21420122 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2833.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21420122 is about 4628.1877662861. The cubic root of 21420122 is about 277.7201002499.

Adding to 21420122 its reverse (22102412), we get a palindrome (43522534).

The spelling of 21420122 in words is "twenty-one million, four hundred twenty thousand, one hundred twenty-two".