21772769 has 2 divisors, whose sum is σ = 21772770. Its totient is φ = 21772768.

The previous prime is 21772759. The next prime is 21772787. The reversal of 21772769 is 96727712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13432225 + 8340544 = 3665^2 + 2888^2 .

It is a cyclic number.

It is not a de Polignac number, because 21772769 - 2²⁴ = 4995553 is a prime.

It is a super-2 number, since 2×21772769² = 948106939854722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21772759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10886384 + 10886385.

It is an arithmetic number, because the mean of its divisors is an integer number (10886385).

Almost surely, 2^21772769 is an apocalyptic number.

It is an amenable number.

21772769 is a deficient number, since it is larger than the sum of its proper divisors (1).

21772769 is an equidigital number, since it uses as much as digits as its factorization.

21772769 is an evil number, because the sum of its binary digits is even.

The product of its digits is 74088, while the sum is 41.

The square root of 21772769 is about 4666.1299810442. The cubic root of 21772769 is about 279.2358800491.

It can be divided in two parts, 2 and 1772769, that added together give a palindrome (1772771).

The spelling of 21772769 in words is "twenty-one million, seven hundred seventy-two thousand, seven hundred sixty-nine".