21912777 has 24 divisors (see below), whose sum is σ = 33321600. Its totient is φ = 13855968.

The previous prime is 21912773. The next prime is 21912791. The reversal of 21912777 is 77721912.

It is not a de Polignac number, because 21912777 - 2² = 21912773 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21912773) 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 23 ways as a sum of consecutive naturals, for example, 14688 + ... + 16110.

It is an arithmetic number, because the mean of its divisors is an integer number (1388400).

Almost surely, 2^21912777 is an apocalyptic number.

It is an amenable number.

21912777 is a deficient number, since it is larger than the sum of its proper divisors (11408823).

21912777 is a wasteful number, since it uses less digits than its factorization.

21912777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1517 (or 1514 counting only the distinct ones).

The product of its digits is 12348, while the sum is 36.

The square root of 21912777 is about 4681.1085225617. The cubic root of 21912777 is about 279.8331361227.

It can be divided in two parts, 219 and 12777, that added together give a square (12996 = 114²).

The spelling of 21912777 in words is "twenty-one million, nine hundred twelve thousand, seven hundred seventy-seven".