21989170 has 32 divisors (see below), whose sum is σ = 46096128. Its totient is φ = 7395648.

The previous prime is 21989159. The next prime is 21989171. The reversal of 21989170 is 7198912.

It is not an unprimeable number, because it can be changed into a prime (21989171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 747 + ... + 6673.

It is an arithmetic number, because the mean of its divisors is an integer number (1440504).

Almost surely, 2^21989170 is an apocalyptic number.

21989170 is an abundant number, since it is smaller than the sum of its proper divisors (24106958).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21989170 is a wasteful number, since it uses less digits than its factorization.

21989170 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5994.

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 21989170 is about 4689.2611358294. The cubic root of 21989170 is about 280.1579466006.

It can be divided in two parts, 219891 and 70, that added together give a square (219961 = 469²).

The spelling of 21989170 in words is "twenty-one million, nine hundred eighty-nine thousand, one hundred seventy".