21447656 has 32 divisors (see below), whose sum is σ = 42660000. Its totient is φ = 10080576.

The previous prime is 21447611. The next prime is 21447683. The reversal of 21447656 is 65674412.

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, 22175 + ... + 23121.

It is an arithmetic number, because the mean of its divisors is an integer number (1333125).

Almost surely, 2^21447656 is an apocalyptic number.

It is an amenable number.

21447656 is a deficient number, since it is larger than the sum of its proper divisors (21212344).

21447656 is a wasteful number, since it uses less digits than its factorization.

21447656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121 (or 1117 counting only the distinct ones).

The product of its digits is 40320, while the sum is 35.

The square root of 21447656 is about 4631.1614094091. The cubic root of 21447656 is about 277.8390455907.

The spelling of 21447656 in words is "twenty-one million, four hundred forty-seven thousand, six hundred fifty-six".