21949927 has 2 divisors, whose sum is σ = 21949928. Its totient is φ = 21949926.

The previous prime is 21949877. The next prime is 21949951. The reversal of 21949927 is 72994912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21949927 - 2¹⁹ = 21425639 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21940927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10974963 + 10974964.

It is an arithmetic number, because the mean of its divisors is an integer number (10974964).

Almost surely, 2^21949927 is an apocalyptic number.

21949927 is a deficient number, since it is larger than the sum of its proper divisors (1).

21949927 is an equidigital number, since it uses as much as digits as its factorization.

21949927 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 43.

The square root of 21949927 is about 4685.0749193583. The cubic root of 21949927 is about 279.9911859470.

It can be divided in two parts, 2194 and 9927, that added together give a palindrome (12121).

The spelling of 21949927 in words is "twenty-one million, nine hundred forty-nine thousand, nine hundred twenty-seven".