21345768 has 40 divisors (see below), whose sum is σ = 59789730. Its totient is φ = 7115040.

The previous prime is 21345767. The next prime is 21345809. The reversal of 21345768 is 86754312.

It can be written as a sum of positive squares in only one way, i.e., 14152644 + 7193124 = 3762^2 + 2682^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21345767) 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 9 ways as a sum of consecutive naturals, for example, 15823 + ... + 17118.

Almost surely, 2^21345768 is an apocalyptic number.

It is an amenable number.

21345768 is an abundant number, since it is smaller than the sum of its proper divisors (38443962).

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

21345768 is a wasteful number, since it uses less digits than its factorization.

21345768 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32959 (or 32946 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21345768 is about 4620.1480495759. The cubic root of 21345768 is about 277.3983850011.

The spelling of 21345768 in words is "twenty-one million, three hundred forty-five thousand, seven hundred sixty-eight".