21738648601 has 2 divisors, whose sum is σ = 21738648602. Its totient is φ = 21738648600.

The previous prime is 21738648583. The next prime is 21738648641. The reversal of 21738648601 is 10684683712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16614952201 + 5123696400 = 128899^2 + 71580^2 .

It is a cyclic number.

It is not a de Polignac number, because 21738648601 - 2¹³ = 21738640409 is a prime.

It is not a weakly prime, because it can be changed into another prime (21738648641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10869324300 + 10869324301.

It is an arithmetic number, because the mean of its divisors is an integer number (10869324301).

Almost surely, 2^21738648601 is an apocalyptic number.

It is an amenable number.

21738648601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21738648601 is an equidigital number, since it uses as much as digits as its factorization.

21738648601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 387072, while the sum is 46.

The spelling of 21738648601 in words is "twenty-one billion, seven hundred thirty-eight million, six hundred forty-eight thousand, six hundred one".