21666876 has 96 divisors (see below), whose sum is σ = 63866880. Its totient is φ = 5553600.

The previous prime is 21666871. The next prime is 21666881. The reversal of 21666876 is 67866612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21666871) and next prime (21666881).

It is a super-3 number, since 3×21666876³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21666871) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 120955 + ... + 121133.

It is an arithmetic number, because the mean of its divisors is an integer number (665280).

Almost surely, 2^21666876 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21666876, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31933440).

21666876 is an abundant number, since it is smaller than the sum of its proper divisors (42200004).

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

21666876 is a wasteful number, since it uses less digits than its factorization.

21666876 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 333 counting only the distinct ones).

The product of its digits is 145152, while the sum is 42.

The square root of 21666876 is about 4654.7691672090. The cubic root of 21666876 is about 278.7824513956.

The spelling of 21666876 in words is "twenty-one million, six hundred sixty-six thousand, eight hundred seventy-six".