21456783 has 12 divisors (see below), whose sum is σ = 31039008. Its totient is φ = 14283360.

The previous prime is 21456767. The next prime is 21456791. The reversal of 21456783 is 38765412.

21456783 is a `hidden beast` number, since 2 + 14 + 567 + 83 = 666.

It is not a de Polignac number, because 21456783 - 2⁴ = 21456767 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21456713) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6891 + ... + 9507.

It is an arithmetic number, because the mean of its divisors is an integer number (2586584).

Almost surely, 2^21456783 is an apocalyptic number.

21456783 is a deficient number, since it is larger than the sum of its proper divisors (9582225).

21456783 is a wasteful number, since it uses less digits than its factorization.

21456783 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3534 (or 3531 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21456783 is about 4632.1466945683. The cubic root of 21456783 is about 277.8784512542.

The spelling of 21456783 in words is "twenty-one million, four hundred fifty-six thousand, seven hundred eighty-three".