21992429 has 4 divisors (see below), whose sum is σ = 22008000. Its totient is φ = 21976860.

The previous prime is 21992417. The next prime is 21992461. The reversal of 21992429 is 92429912.

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 a de Polignac number, because none of the positive numbers 2^k-21992429 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21992392 and 21992401.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992129) 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, 5429 + ... + 8570.

It is an arithmetic number, because the mean of its divisors is an integer number (5502000).

Almost surely, 2^21992429 is an apocalyptic number.

It is an amenable number.

21992429 is a deficient number, since it is larger than the sum of its proper divisors (15571).

21992429 is a wasteful number, since it uses less digits than its factorization.

21992429 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15570.

The product of its digits is 23328, while the sum is 38.

The square root of 21992429 is about 4689.6086190641. The cubic root of 21992429 is about 280.1717865901.

The spelling of 21992429 in words is "twenty-one million, nine hundred ninety-two thousand, four hundred twenty-nine".