21214429 has 2 divisors, whose sum is σ = 21214430. Its totient is φ = 21214428.

The previous prime is 21214381. The next prime is 21214433. The reversal of 21214429 is 92441212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20457529 + 756900 = 4523^2 + 870^2 .

It is a cyclic number.

It is not a de Polignac number, because 21214429 - 2²³ = 12825821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21214229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10607214 + 10607215.

It is an arithmetic number, because the mean of its divisors is an integer number (10607215).

Almost surely, 2^21214429 is an apocalyptic number.

It is an amenable number.

21214429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21214429 is an equidigital number, since it uses as much as digits as its factorization.

21214429 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 25.

The square root of 21214429 is about 4605.9123960405. The cubic root of 21214429 is about 276.8282765741.

It can be divided in two parts, 212 and 14429, that added together give a palindrome (14641).

The spelling of 21214429 in words is "twenty-one million, two hundred fourteen thousand, four hundred twenty-nine".