21640662229 has 2 divisors, whose sum is σ = 21640662230. Its totient is φ = 21640662228.

The previous prime is 21640662203. The next prime is 21640662233. The reversal of 21640662229 is 92226604612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21454339729 + 186322500 = 146473^2 + 13650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21640662229 - 2¹³ = 21640654037 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21640662191 and 21640662200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21640662259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10820331114 + 10820331115.

It is an arithmetic number, because the mean of its divisors is an integer number (10820331115).

Almost surely, 2^21640662229 is an apocalyptic number.

It is an amenable number.

21640662229 is a deficient number, since it is larger than the sum of its proper divisors (1).

21640662229 is an equidigital number, since it uses as much as digits as its factorization.

21640662229 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 124416, while the sum is 40.

The spelling of 21640662229 in words is "twenty-one billion, six hundred forty million, six hundred sixty-two thousand, two hundred twenty-nine".