21946929 has 16 divisors (see below), whose sum is σ = 30143232. Its totient is φ = 14197248.

The previous prime is 21946909. The next prime is 21946937. The reversal of 21946929 is 92964912.

It is not a de Polignac number, because 21946929 - 2¹⁵ = 21914161 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21946909) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14712 + ... + 16134.

It is an arithmetic number, because the mean of its divisors is an integer number (1883952).

Almost surely, 2^21946929 is an apocalyptic number.

It is an amenable number.

21946929 is a deficient number, since it is larger than the sum of its proper divisors (8196303).

21946929 is a wasteful number, since it uses less digits than its factorization.

21946929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1576.

The product of its digits is 69984, while the sum is 42.

The square root of 21946929 is about 4684.7549562384. The cubic root of 21946929 is about 279.9784379655.

The spelling of 21946929 in words is "twenty-one million, nine hundred forty-six thousand, nine hundred twenty-nine".