21750164 has 12 divisors (see below), whose sum is σ = 38337600. Its totient is φ = 10796568.

The previous prime is 21750163. The next prime is 21750181. The reversal of 21750164 is 46105712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21750161) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19004 + ... + 20115.

It is an arithmetic number, because the mean of its divisors is an integer number (3194800).

Almost surely, 2^21750164 is an apocalyptic number.

It is an amenable number.

21750164 is a deficient number, since it is larger than the sum of its proper divisors (16587436).

21750164 is a wasteful number, since it uses less digits than its factorization.

21750164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39262 (or 39260 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21750164 is about 4663.7071091568. The cubic root of 21750164 is about 279.1392101707.

Adding to 21750164 its reverse (46105712), we get a palindrome (67855876).

The spelling of 21750164 in words is "twenty-one million, seven hundred fifty thousand, one hundred sixty-four".