21947736 has 32 divisors (see below), whose sum is σ = 57758400. Its totient is φ = 6930720.

The previous prime is 21947729. The next prime is 21947741. The reversal of 21947736 is 63774912.

It is a junction number, because it is equal to n+sod(n) for n = 21947694 and 21947703.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23610 + ... + 24521.

It is an arithmetic number, because the mean of its divisors is an integer number (1804950).

Almost surely, 2^21947736 is an apocalyptic number.

It is an amenable number.

21947736 is an abundant number, since it is smaller than the sum of its proper divisors (35810664).

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

21947736 is a wasteful number, since it uses less digits than its factorization.

21947736 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48159 (or 48155 counting only the distinct ones).

The product of its digits is 63504, while the sum is 39.

The square root of 21947736 is about 4684.8410858854. The cubic root of 21947736 is about 279.9818695744.

The spelling of 21947736 in words is "twenty-one million, nine hundred forty-seven thousand, seven hundred thirty-six".