21792929 has 4 divisors (see below), whose sum is σ = 23074884. Its totient is φ = 20510976.

The previous prime is 21792923. The next prime is 21792931. The reversal of 21792929 is 92929712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18258529 + 3534400 = 4273^2 + 1880^2 .

It is not a de Polignac number, because 21792929 - 2²⁴ = 5015713 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21792923) 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, 640952 + ... + 640985.

It is an arithmetic number, because the mean of its divisors is an integer number (5768721).

Almost surely, 2^21792929 is an apocalyptic number.

It is an amenable number.

21792929 is a deficient number, since it is larger than the sum of its proper divisors (1281955).

21792929 is a wasteful number, since it uses less digits than its factorization.

21792929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1281954.

The product of its digits is 40824, while the sum is 41.

The square root of 21792929 is about 4668.2897296547. The cubic root of 21792929 is about 279.3220374990.

The spelling of 21792929 in words is "twenty-one million, seven hundred ninety-two thousand, nine hundred twenty-nine".