21443629 has 2 divisors, whose sum is σ = 21443630. Its totient is φ = 21443628.

The previous prime is 21443623. The next prime is 21443657. The reversal of 21443629 is 92634412.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21178404 + 265225 = 4602^2 + 515^2 .

It is a cyclic number.

It is not a de Polignac number, because 21443629 - 2³ = 21443621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21443629.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21443621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10721814 + 10721815.

It is an arithmetic number, because the mean of its divisors is an integer number (10721815).

Almost surely, 2^21443629 is an apocalyptic number.

It is an amenable number.

21443629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21443629 is an equidigital number, since it uses as much as digits as its factorization.

21443629 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 31.

The square root of 21443629 is about 4630.7266168497. The cubic root of 21443629 is about 277.8216555339.

The spelling of 21443629 in words is "twenty-one million, four hundred forty-three thousand, six hundred twenty-nine".