21970650649 has 2 divisors, whose sum is σ = 21970650650. Its totient is φ = 21970650648.

The previous prime is 21970650601. The next prime is 21970650671. The reversal of 21970650649 is 94605607912.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17499321225 + 4471329424 = 132285^2 + 66868^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21970650649 is a prime.

It is not a weakly prime, because it can be changed into another prime (21970650679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985325324 + 10985325325.

It is an arithmetic number, because the mean of its divisors is an integer number (10985325325).

Almost surely, 2^21970650649 is an apocalyptic number.

It is an amenable number.

21970650649 is a deficient number, since it is larger than the sum of its proper divisors (1).

21970650649 is an equidigital number, since it uses as much as digits as its factorization.

21970650649 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 816480, while the sum is 49.

The spelling of 21970650649 in words is "twenty-one billion, nine hundred seventy million, six hundred fifty thousand, six hundred forty-nine".