21290629 has 2 divisors, whose sum is σ = 21290630. Its totient is φ = 21290628.

The previous prime is 21290623. The next prime is 21290641. The reversal of 21290629 is 92609212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21178404 + 112225 = 4602^2 + 335^2 .

It is a cyclic number.

It is not a de Polignac number, because 21290629 - 2⁵ = 21290597 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21290629.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21290623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10645314 + 10645315.

It is an arithmetic number, because the mean of its divisors is an integer number (10645315).

Almost surely, 2^21290629 is an apocalyptic number.

It is an amenable number.

21290629 is a deficient number, since it is larger than the sum of its proper divisors (1).

21290629 is an equidigital number, since it uses as much as digits as its factorization.

21290629 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 21290629 is about 4614.1769580284. The cubic root of 21290629 is about 277.1593265522.

The spelling of 21290629 in words is "twenty-one million, two hundred ninety thousand, six hundred twenty-nine".