21969705 has 16 divisors (see below), whose sum is σ = 35291520. Its totient is φ = 11670528.

The previous prime is 21969691. The next prime is 21969709. The reversal of 21969705 is 50796912.

It is not a de Polignac number, because 21969705 - 2⁶ = 21969641 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21969709) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1161 + ... + 6729.

It is an arithmetic number, because the mean of its divisors is an integer number (2205720).

Almost surely, 2^21969705 is an apocalyptic number.

It is an amenable number.

21969705 is a deficient number, since it is larger than the sum of its proper divisors (13321815).

21969705 is a wasteful number, since it uses less digits than its factorization.

21969705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5840.

The product of its (nonzero) digits is 34020, while the sum is 39.

The square root of 21969705 is about 4687.1851894287. The cubic root of 21969705 is about 280.0752561320.

The spelling of 21969705 in words is "twenty-one million, nine hundred sixty-nine thousand, seven hundred five".