21273429 has 4 divisors (see below), whose sum is σ = 28364576. Its totient is φ = 14182284.

The previous prime is 21273391. The next prime is 21273431. The reversal of 21273429 is 92437212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21273429 - 2¹¹ = 21271381 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21273396 and 21273405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21273449) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3545569 + ... + 3545574.

It is an arithmetic number, because the mean of its divisors is an integer number (7091144).

Almost surely, 2^21273429 is an apocalyptic number.

It is an amenable number.

21273429 is a deficient number, since it is larger than the sum of its proper divisors (7091147).

21273429 is an equidigital number, since it uses as much as digits as its factorization.

21273429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7091146.

The product of its digits is 6048, while the sum is 30.

The square root of 21273429 is about 4612.3127604272. The cubic root of 21273429 is about 277.0846704717.

The spelling of 21273429 in words is "twenty-one million, two hundred seventy-three thousand, four hundred twenty-nine".