21768550 has 12 divisors (see below), whose sum is σ = 40489596. Its totient is φ = 8707400.

The previous prime is 21768533. The next prime is 21768553. The reversal of 21768550 is 5586712.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21768553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 217636 + ... + 217735.

It is an arithmetic number, because the mean of its divisors is an integer number (3374133).

Almost surely, 2^21768550 is an apocalyptic number.

21768550 is a deficient number, since it is larger than the sum of its proper divisors (18721046).

21768550 is a wasteful number, since it uses less digits than its factorization.

21768550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435383 (or 435378 counting only the distinct ones).

The product of its (nonzero) digits is 16800, while the sum is 34.

The square root of 21768550 is about 4665.6778714352. The cubic root of 21768550 is about 279.2178426514.

The spelling of 21768550 in words is "twenty-one million, seven hundred sixty-eight thousand, five hundred fifty".