21152166 has 16 divisors (see below), whose sum is σ = 48347904. Its totient is φ = 6043464.

The previous prime is 21152143. The next prime is 21152207. The reversal of 21152166 is 66125112.

It is a super-3 number, since 3×21152166³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 251770 + ... + 251853.

It is an arithmetic number, because the mean of its divisors is an integer number (3021744).

Almost surely, 2^21152166 is an apocalyptic number.

21152166 is an abundant number, since it is smaller than the sum of its proper divisors (27195738).

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

21152166 is a wasteful number, since it uses less digits than its factorization.

21152166 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 503635.

The product of its digits is 720, while the sum is 24.

The square root of 21152166 is about 4599.1483994322. The cubic root of 21152166 is about 276.5571867280.

Adding to 21152166 its reverse (66125112), we get a palindrome (87277278).

The spelling of 21152166 in words is "twenty-one million, one hundred fifty-two thousand, one hundred sixty-six".