21771053 has 2 divisors, whose sum is σ = 21771054. Its totient is φ = 21771052.

The previous prime is 21771049. The next prime is 21771077. The reversal of 21771053 is 35017712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18992164 + 2778889 = 4358^2 + 1667^2 .

It is a cyclic number.

It is not a de Polignac number, because 21771053 - 2² = 21771049 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21771353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10885526 + 10885527.

It is an arithmetic number, because the mean of its divisors is an integer number (10885527).

Almost surely, 2^21771053 is an apocalyptic number.

It is an amenable number.

21771053 is a deficient number, since it is larger than the sum of its proper divisors (1).

21771053 is an equidigital number, since it uses as much as digits as its factorization.

21771053 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1470, while the sum is 26.

The square root of 21771053 is about 4665.9460991315. The cubic root of 21771053 is about 279.2285439533.

Adding to 21771053 its reverse (35017712), we get a palindrome (56788765).

The spelling of 21771053 in words is "twenty-one million, seven hundred seventy-one thousand, fifty-three".