21457783 has 8 divisors (see below), whose sum is σ = 22630400. Its totient is φ = 20289528.

The previous prime is 21457771. The next prime is 21457819. The reversal of 21457783 is 38775412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21457783 - 2²¹ = 19360631 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21457703) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16138 + ... + 17416.

It is an arithmetic number, because the mean of its divisors is an integer number (2828800).

Almost surely, 2^21457783 is an apocalyptic number.

21457783 is a deficient number, since it is larger than the sum of its proper divisors (1172617).

21457783 is a wasteful number, since it uses less digits than its factorization.

21457783 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2181.

The product of its digits is 47040, while the sum is 37.

The square root of 21457783 is about 4632.2546346245. The cubic root of 21457783 is about 277.8827680575.

The spelling of 21457783 in words is "twenty-one million, four hundred fifty-seven thousand, seven hundred eighty-three".