21022002649 has 2 divisors, whose sum is σ = 21022002650. Its totient is φ = 21022002648.

The previous prime is 21022002643. The next prime is 21022002697. The reversal of 21022002649 is 94620022012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20762792649 + 259210000 = 144093^2 + 16100^2 .

It is a cyclic number.

It is not a de Polignac number, because 21022002649 - 2²⁷ = 20887784921 is a prime.

It is not a weakly prime, because it can be changed into another prime (21022002643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511001324 + 10511001325.

It is an arithmetic number, because the mean of its divisors is an integer number (10511001325).

Almost surely, 2^21022002649 is an apocalyptic number.

It is an amenable number.

21022002649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21022002649 is an equidigital number, since it uses as much as digits as its factorization.

21022002649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 28.

The spelling of 21022002649 in words is "twenty-one billion, twenty-two million, two thousand, six hundred forty-nine".