21292429 has 2 divisors, whose sum is σ = 21292430. Its totient is φ = 21292428.

The previous prime is 21292423. The next prime is 21292433. The reversal of 21292429 is 92429212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11744329 + 9548100 = 3427^2 + 3090^2 .

It is a cyclic number.

It is not a de Polignac number, because 21292429 - 2¹⁹ = 20768141 is a prime.

It is equal to p_1347295 and since 21292429 and 1347295 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21292429.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21292423) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10646214 + 10646215.

It is an arithmetic number, because the mean of its divisors is an integer number (10646215).

Almost surely, 2^21292429 is an apocalyptic number.

It is an amenable number.

21292429 is a deficient number, since it is larger than the sum of its proper divisors (1).

21292429 is an equidigital number, since it uses as much as digits as its factorization.

21292429 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 31.

The square root of 21292429 is about 4614.3720049428. The cubic root of 21292429 is about 277.1671370734.

The spelling of 21292429 in words is "twenty-one million, two hundred ninety-two thousand, four hundred twenty-nine".