21770705 has 16 divisors (see below), whose sum is σ = 28987200. Its totient is φ = 15562560.

The previous prime is 21770701. The next prime is 21770731. The reversal of 21770705 is 50707712.

It is not a de Polignac number, because 21770705 - 2² = 21770701 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21770701) 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 15 ways as a sum of consecutive naturals, for example, 110 + ... + 6599.

It is an arithmetic number, because the mean of its divisors is an integer number (1811700).

Almost surely, 2^21770705 is an apocalyptic number.

It is an amenable number.

21770705 is a deficient number, since it is larger than the sum of its proper divisors (7216495).

21770705 is a wasteful number, since it uses less digits than its factorization.

21770705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6784.

The product of its (nonzero) digits is 3430, while the sum is 29.

The square root of 21770705 is about 4665.9088075101. The cubic root of 21770705 is about 279.2270561665.

The spelling of 21770705 in words is "twenty-one million, seven hundred seventy thousand, seven hundred five".