21505674 has 16 divisors (see below), whose sum is σ = 43206912. Its totient is φ = 7135968.

The previous prime is 21505643. The next prime is 21505681. The reversal of 21505674 is 47650512.

It is a Curzon number.

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, 6699 + ... + 9374.

It is an arithmetic number, because the mean of its divisors is an integer number (2700432).

Almost surely, 2^21505674 is an apocalyptic number.

21505674 is an abundant number, since it is smaller than the sum of its proper divisors (21701238).

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

21505674 is a wasteful number, since it uses less digits than its factorization.

21505674 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16301.

The product of its (nonzero) digits is 8400, while the sum is 30.

The square root of 21505674 is about 4637.4210505409. The cubic root of 21505674 is about 278.0893472626.

The spelling of 21505674 in words is "twenty-one million, five hundred five thousand, six hundred seventy-four".