21945707 has 8 divisors (see below), whose sum is σ = 25220832. Its totient is φ = 18705600.

The previous prime is 21945689. The next prime is 21945751. The reversal of 21945707 is 70754912.

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 21945707 - 2⁶ = 21945643 is a prime.

It is a super-2 number, since 2×21945707² = 963228111459698, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21945797) 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, 7394 + ... + 9927.

It is an arithmetic number, because the mean of its divisors is an integer number (3152604).

Almost surely, 2^21945707 is an apocalyptic number.

21945707 is a deficient number, since it is larger than the sum of its proper divisors (3275125).

21945707 is a wasteful number, since it uses less digits than its factorization.

21945707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17509.

The product of its (nonzero) digits is 17640, while the sum is 35.

The square root of 21945707 is about 4684.6245313792. The cubic root of 21945707 is about 279.9732414905.

The spelling of 21945707 in words is "twenty-one million, nine hundred forty-five thousand, seven hundred seven".