21829493 has 4 divisors (see below), whose sum is σ = 24948000. Its totient is φ = 18710988.

The previous prime is 21829477. The next prime is 21829501. The reversal of 21829493 is 39492812.

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 a cyclic number.

It is not a de Polignac number, because 21829493 - 2⁴ = 21829477 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21829463) 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, 1559243 + ... + 1559256.

It is an arithmetic number, because the mean of its divisors is an integer number (6237000).

Almost surely, 2^21829493 is an apocalyptic number.

It is an amenable number.

21829493 is a deficient number, since it is larger than the sum of its proper divisors (3118507).

21829493 is an equidigital number, since it uses as much as digits as its factorization.

21829493 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3118506.

The product of its digits is 31104, while the sum is 38.

The square root of 21829493 is about 4672.2042977592. The cubic root of 21829493 is about 279.4781649668.

It can be divided in two parts, 21829 and 493, that added together give a palindrome (22322).

The spelling of 21829493 in words is "twenty-one million, eight hundred twenty-nine thousand, four hundred ninety-three".