21402122 has 12 divisors (see below), whose sum is σ = 37344690. Its totient is φ = 9172296.

The previous prime is 21402119. The next prime is 21402137. The reversal of 21402122 is 22120412.

It can be written as a sum of positive squares in only one way, i.e., 18412681 + 2989441 = 4291^2 + 1729^2 .

It is a super-2 number, since 2×21402122² = 916101652205768, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (14).

It is a junction number, because it is equal to n+sod(n) for n = 21402097 and 21402106.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109097 + ... + 109292.

Almost surely, 2^21402122 is an apocalyptic number.

21402122 is a deficient number, since it is larger than the sum of its proper divisors (15942568).

21402122 is a wasteful number, since it uses less digits than its factorization.

21402122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 218405 (or 218398 counting only the distinct ones).

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

The square root of 21402122 is about 4626.2427519533. The cubic root of 21402122 is about 277.6422861472.

Adding to 21402122 its reverse (22120412), we get a palindrome (43522534).

The spelling of 21402122 in words is "twenty-one million, four hundred two thousand, one hundred twenty-two".