21791634 has 16 divisors (see below), whose sum is σ = 43636320. Its totient is φ = 7255040.

The previous prime is 21791629. The next prime is 21791641. The reversal of 21791634 is 43619712.

It is a Smith number, since the sum of its digits (33) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21791595 and 21791604.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4882 + ... + 8210.

It is an arithmetic number, because the mean of its divisors is an integer number (2727270).

Almost surely, 2^21791634 is an apocalyptic number.

21791634 is an abundant number, since it is smaller than the sum of its proper divisors (21844686).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21791634 is a wasteful number, since it uses less digits than its factorization.

21791634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4425.

The product of its digits is 9072, while the sum is 33.

The square root of 21791634 is about 4668.1510258345. The cubic root of 21791634 is about 279.3165046768.

The spelling of 21791634 in words is "twenty-one million, seven hundred ninety-one thousand, six hundred thirty-four".