21091336 has 16 divisors (see below), whose sum is σ = 45195840. Its totient is φ = 9039120.

The previous prime is 21091333. The next prime is 21091351. The reversal of 21091336 is 63319012.

It is a self number, because there is not a number n which added to its sum of digits gives 21091336.

It is not an unprimeable number, because it can be changed into a prime (21091333) 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, 188260 + ... + 188371.

It is an arithmetic number, because the mean of its divisors is an integer number (2824740).

Almost surely, 2^21091336 is an apocalyptic number.

It is an amenable number.

21091336 is an abundant number, since it is smaller than the sum of its proper divisors (24104504).

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

21091336 is a wasteful number, since it uses less digits than its factorization.

21091336 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 376644 (or 376640 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 21091336 is about 4592.5304571663. The cubic root of 21091336 is about 276.2918218454.

The spelling of 21091336 in words is "twenty-one million, ninety-one thousand, three hundred thirty-six".