21170090 has 16 divisors (see below), whose sum is σ = 38158560. Its totient is φ = 8456400.

The previous prime is 21170077. The next prime is 21170099. The reversal of 21170090 is 9007112.

It is not an unprimeable number, because it can be changed into a prime (21170099) 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 7 ways as a sum of consecutive naturals, for example, 13781 + ... + 15239.

It is an arithmetic number, because the mean of its divisors is an integer number (2384910).

Almost surely, 2^21170090 is an apocalyptic number.

21170090 is a deficient number, since it is larger than the sum of its proper divisors (16988470).

21170090 is a wasteful number, since it uses less digits than its factorization.

21170090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2917.

The product of its (nonzero) digits is 126, while the sum is 20.

The square root of 21170090 is about 4601.0966084185. The cubic root of 21170090 is about 276.6352813545.

The spelling of 21170090 in words is "twenty-one million, one hundred seventy thousand, ninety".