21929505 has 16 divisors (see below), whose sum is σ = 37786560. Its totient is φ = 10795968.

The previous prime is 21929503. The next prime is 21929519. The reversal of 21929505 is 50592912.

It is not a de Polignac number, because 21929505 - 2¹ = 21929503 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21929503) 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, 56035 + ... + 56424.

It is an arithmetic number, because the mean of its divisors is an integer number (2361660).

Almost surely, 2^21929505 is an apocalyptic number.

It is an amenable number.

21929505 is a deficient number, since it is larger than the sum of its proper divisors (15857055).

21929505 is a wasteful number, since it uses less digits than its factorization.

21929505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112480.

The product of its (nonzero) digits is 8100, while the sum is 33.

The square root of 21929505 is about 4682.8949379631. The cubic root of 21929505 is about 279.9043253053.

The spelling of 21929505 in words is "twenty-one million, nine hundred twenty-nine thousand, five hundred five".