21429613 has 2 divisors, whose sum is σ = 21429614. Its totient is φ = 21429612.

The previous prime is 21429589. The next prime is 21429641. The reversal of 21429613 is 31692412.

It is an a-pointer prime, because the next prime (21429641) can be obtained adding 21429613 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11202409 + 10227204 = 3347^2 + 3198^2 .

It is a cyclic number.

It is not a de Polignac number, because 21429613 - 2⁵ = 21429581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21429643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10714806 + 10714807.

It is an arithmetic number, because the mean of its divisors is an integer number (10714807).

Almost surely, 2^21429613 is an apocalyptic number.

It is an amenable number.

21429613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21429613 is an equidigital number, since it uses as much as digits as its factorization.

21429613 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 28.

The square root of 21429613 is about 4629.2130000682. The cubic root of 21429613 is about 277.7611123454.

The spelling of 21429613 in words is "twenty-one million, four hundred twenty-nine thousand, six hundred thirteen".