21366777 has 8 divisors (see below), whose sum is σ = 28510720. Its totient is φ = 14233680.

The previous prime is 21366767. The next prime is 21366803. The reversal of 21366777 is 77766312.

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

It is not a de Polignac number, because 21366777 - 2⁶ = 21366713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21366727) by changing a digit.

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, 5127 + ... + 8307.

It is an arithmetic number, because the mean of its divisors is an integer number (3563840).

Almost surely, 2^21366777 is an apocalyptic number.

It is an amenable number.

21366777 is a deficient number, since it is larger than the sum of its proper divisors (7143943).

21366777 is a wasteful number, since it uses less digits than its factorization.

21366777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5423.

The product of its digits is 74088, while the sum is 39.

The square root of 21366777 is about 4622.4211188510. The cubic root of 21366777 is about 277.4893624686.

The spelling of 21366777 in words is "twenty-one million, three hundred sixty-six thousand, seven hundred seventy-seven".