21636774 has 16 divisors (see below), whose sum is σ = 48081840. Its totient is φ = 7212240.

The previous prime is 21636743. The next prime is 21636781. The reversal of 21636774 is 47763612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200287 + ... + 200394.

It is an arithmetic number, because the mean of its divisors is an integer number (3005115).

Almost surely, 2^21636774 is an apocalyptic number.

21636774 is an abundant number, since it is smaller than the sum of its proper divisors (26445066).

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

21636774 is a wasteful number, since it uses less digits than its factorization.

21636774 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400692 (or 400686 counting only the distinct ones).

The product of its digits is 42336, while the sum is 36.

The square root of 21636774 is about 4651.5345854890. The cubic root of 21636774 is about 278.6532865101.

The spelling of 21636774 in words is "twenty-one million, six hundred thirty-six thousand, seven hundred seventy-four".