21774289 has 2 divisors, whose sum is σ = 21774290. Its totient is φ = 21774288.

The previous prime is 21774281. The next prime is 21774317. The reversal of 21774289 is 98247712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15484225 + 6290064 = 3935^2 + 2508^2 .

It is a cyclic number.

It is not a de Polignac number, because 21774289 - 2³ = 21774281 is a prime.

It is a super-2 number, since 2×21774289² = 948239322911042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21774281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10887144 + 10887145.

It is an arithmetic number, because the mean of its divisors is an integer number (10887145).

Almost surely, 2^21774289 is an apocalyptic number.

It is an amenable number.

21774289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21774289 is an equidigital number, since it uses as much as digits as its factorization.

21774289 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56448, while the sum is 40.

The square root of 21774289 is about 4666.2928540759. The cubic root of 21774289 is about 279.2423779006.

The spelling of 21774289 in words is "twenty-one million, seven hundred seventy-four thousand, two hundred eighty-nine".