21772969 has 2 divisors, whose sum is σ = 21772970. Its totient is φ = 21772968.

The previous prime is 21772967. The next prime is 21772987. The reversal of 21772969 is 96927712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16297369 + 5475600 = 4037^2 + 2340^2 .

It is a cyclic number.

It is not a de Polignac number, because 21772969 - 2¹ = 21772967 is a prime.

It is a super-2 number, since 2×21772969² = 948124358149922, which contains 22 as substring.

Together with 21772967, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21772963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10886484 + 10886485.

It is an arithmetic number, because the mean of its divisors is an integer number (10886485).

Almost surely, 2^21772969 is an apocalyptic number.

It is an amenable number.

21772969 is a deficient number, since it is larger than the sum of its proper divisors (1).

21772969 is an equidigital number, since it uses as much as digits as its factorization.

21772969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 95256, while the sum is 43.

The square root of 21772969 is about 4666.1514120311. The cubic root of 21772969 is about 279.2367350468.

The spelling of 21772969 in words is "twenty-one million, seven hundred seventy-two thousand, nine hundred sixty-nine".