21677705 has 8 divisors (see below), whose sum is σ = 29729472. Its totient is φ = 14864688.

The previous prime is 21677701. The next prime is 21677713. The reversal of 21677705 is 50777612.

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 21677705 - 2² = 21677701 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35), and also a Moran number because the ratio is a prime number: 619363 = 21677705 / (2 + 1 + 6 + 7 + 7 + 7 + 0 + 5).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21677701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 309647 + ... + 309716.

It is an arithmetic number, because the mean of its divisors is an integer number (3716184).

Almost surely, 2^21677705 is an apocalyptic number.

It is an amenable number.

21677705 is a deficient number, since it is larger than the sum of its proper divisors (8051767).

21677705 is an equidigital number, since it uses as much as digits as its factorization.

21677705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 619375.

The product of its (nonzero) digits is 20580, while the sum is 35.

The square root of 21677705 is about 4655.9322374794. The cubic root of 21677705 is about 278.8288883679.

The spelling of 21677705 in words is "twenty-one million, six hundred seventy-seven thousand, seven hundred five".