21772057 has 2 divisors, whose sum is σ = 21772058. Its totient is φ = 21772056.

The previous prime is 21772033. The next prime is 21772063. The reversal of 21772057 is 75027712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13075456 + 8696601 = 3616^2 + 2949^2 .

It is a cyclic number.

It is not a de Polignac number, because 21772057 - 2¹⁹ = 21247769 is a prime.

It is a super-2 number, since 2×21772057² = 948044932022498, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21772067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10886028 + 10886029.

It is an arithmetic number, because the mean of its divisors is an integer number (10886029).

Almost surely, 2^21772057 is an apocalyptic number.

It is an amenable number.

21772057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21772057 is an equidigital number, since it uses as much as digits as its factorization.

21772057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6860, while the sum is 31.

The square root of 21772057 is about 4666.0536859320. The cubic root of 21772057 is about 279.2328362146.

Adding to 21772057 its reverse (75027712), we get a palindrome (96799769).

The spelling of 21772057 in words is "twenty-one million, seven hundred seventy-two thousand, fifty-seven".