21946429 has 4 divisors (see below), whose sum is σ = 21964576. Its totient is φ = 21928284.

The previous prime is 21946427. The next prime is 21946447. The reversal of 21946429 is 92464912.

It is a happy number.

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 21946429 - 2¹ = 21946427 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21946423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7119 + ... + 9724.

It is an arithmetic number, because the mean of its divisors is an integer number (5491144).

Almost surely, 2^21946429 is an apocalyptic number.

It is an amenable number.

21946429 is a deficient number, since it is larger than the sum of its proper divisors (18147).

21946429 is a wasteful number, since it uses less digits than its factorization.

21946429 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18146.

The product of its digits is 31104, while the sum is 37.

The square root of 21946429 is about 4684.7015913503. The cubic root of 21946429 is about 279.9763117715.

The spelling of 21946429 in words is "twenty-one million, nine hundred forty-six thousand, four hundred twenty-nine".