21905570 has 32 divisors (see below), whose sum is σ = 40383360. Its totient is φ = 8553600.

The previous prime is 21905531. The next prime is 21905573. The reversal of 21905570 is 7550912.

It is not an unprimeable number, because it can be changed into a prime (21905573) 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, 134309 + ... + 134471.

It is an arithmetic number, because the mean of its divisors is an integer number (1261980).

Almost surely, 2^21905570 is an apocalyptic number.

21905570 is a deficient number, since it is larger than the sum of its proper divisors (18477790).

21905570 is a wasteful number, since it uses less digits than its factorization.

21905570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410.

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 21905570 is about 4680.3386629602. The cubic root of 21905570 is about 279.8024541975.

The spelling of 21905570 in words is "twenty-one million, nine hundred five thousand, five hundred seventy".