21429893 has 2 divisors, whose sum is σ = 21429894. Its totient is φ = 21429892.

The previous prime is 21429887. The next prime is 21429899. The reversal of 21429893 is 39892412.

It is a balanced prime because it is at equal distance from previous prime (21429887) and next prime (21429899).

It can be written as a sum of positive squares in only one way, i.e., 18164644 + 3265249 = 4262^2 + 1807^2 .

It is a cyclic number.

It is not a de Polignac number, because 21429893 - 2²⁴ = 4652677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21429899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10714946 + 10714947.

It is an arithmetic number, because the mean of its divisors is an integer number (10714947).

Almost surely, 2^21429893 is an apocalyptic number.

It is an amenable number.

21429893 is a deficient number, since it is larger than the sum of its proper divisors (1).

21429893 is an equidigital number, since it uses as much as digits as its factorization.

21429893 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31104, while the sum is 38.

The square root of 21429893 is about 4629.2432426910. The cubic root of 21429893 is about 277.7623220852.

It can be divided in two parts, 21429 and 893, that added together give a palindrome (22322).

The spelling of 21429893 in words is "twenty-one million, four hundred twenty-nine thousand, eight hundred ninety-three".