21955705 has 8 divisors (see below), whose sum is σ = 26989704. Its totient is φ = 17136000.

The previous prime is 21955691. The next prime is 21955709. The reversal of 21955705 is 50755912.

21955705 = 360² + 361² + ... + 482².

It can be written as a sum of positive squares in 4 ways, for example, as 1498176 + 20457529 = 1224^2 + 4523^2 .

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

It is not a de Polignac number, because 21955705 - 2⁵ = 21955673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21955709) 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, 53346 + ... + 53755.

It is an arithmetic number, because the mean of its divisors is an integer number (3373713).

Almost surely, 2^21955705 is an apocalyptic number.

It is an amenable number.

21955705 is a deficient number, since it is larger than the sum of its proper divisors (5033999).

21955705 is a wasteful number, since it uses less digits than its factorization.

21955705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107147.

The product of its (nonzero) digits is 15750, while the sum is 34.

The square root of 21955705 is about 4685.6915178018. The cubic root of 21955705 is about 280.0157516649.

The spelling of 21955705 in words is "twenty-one million, nine hundred fifty-five thousand, seven hundred five".