21373771 has 2 divisors, whose sum is σ = 21373772. Its totient is φ = 21373770.

The previous prime is 21373717. The next prime is 21373799. The reversal of 21373771 is 17737312.

Together with previous prime (21373717) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21373771 - 2¹³ = 21365579 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21373711) 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 as a sum of consecutive naturals, namely, 10686885 + 10686886.

It is an arithmetic number, because the mean of its divisors is an integer number (10686886).

Almost surely, 2^21373771 is an apocalyptic number.

21373771 is a deficient number, since it is larger than the sum of its proper divisors (1).

21373771 is an equidigital number, since it uses as much as digits as its factorization.

21373771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6174, while the sum is 31.

The square root of 21373771 is about 4623.1775868984. The cubic root of 21373771 is about 277.5196360858.

It can be divided in two parts, 213 and 73771, that added together give a square (73984 = 272²).

The spelling of 21373771 in words is "twenty-one million, three hundred seventy-three thousand, seven hundred seventy-one".