21165429 has 4 divisors (see below), whose sum is σ = 28220576. Its totient is φ = 14110284.

The previous prime is 21165427. The next prime is 21165457. The reversal of 21165429 is 92456112.

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 21165429 - 2¹ = 21165427 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21165396 and 21165405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165421) 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, 3527569 + ... + 3527574.

It is an arithmetic number, because the mean of its divisors is an integer number (7055144).

Almost surely, 2^21165429 is an apocalyptic number.

It is an amenable number.

21165429 is a deficient number, since it is larger than the sum of its proper divisors (7055147).

21165429 is an equidigital number, since it uses as much as digits as its factorization.

21165429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7055146.

The product of its digits is 4320, while the sum is 30.

The square root of 21165429 is about 4600.5900708496. The cubic root of 21165429 is about 276.6149776826.

The spelling of 21165429 in words is "twenty-one million, one hundred sixty-five thousand, four hundred twenty-nine".