21230776 has 32 divisors (see below), whose sum is σ = 46080000. Its totient is φ = 8981856.

The previous prime is 21230767. The next prime is 21230789. The reversal of 21230776 is 67703212.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 2025 + ... + 6823.

It is an arithmetic number, because the mean of its divisors is an integer number (1440000).

Almost surely, 2^21230776 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 21230776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23040000).

21230776 is an abundant number, since it is smaller than the sum of its proper divisors (24849224).

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

21230776 is a wasteful number, since it uses less digits than its factorization.

21230776 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4891 (or 4887 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 28.

The square root of 21230776 is about 4607.6866212884. The cubic root of 21230776 is about 276.8993626258.

Adding to 21230776 its reverse (67703212), we get a palindrome (88933988).

The spelling of 21230776 in words is "twenty-one million, two hundred thirty thousand, seven hundred seventy-six".