1940764638521 has 2 divisors, whose sum is σ = 1940764638522. Its totient is φ = 1940764638520.

The previous prime is 1940764638511. The next prime is 1940764638539. The reversal of 1940764638521 is 1258364670491.

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., 1469428840000 + 471335798521 = 1212200^2 + 686539^2 .

It is an emirp because it is prime and its reverse (1258364670491) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1940764638521 - 2⁶ = 1940764638457 is a prime.

It is not a weakly prime, because it can be changed into another prime (1940764638511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 970382319260 + 970382319261.

It is an arithmetic number, because the mean of its divisors is an integer number (970382319261).

It is a 1-persistent number, because it is pandigital, but 2⋅1940764638521 = 3881529277042 is not.

Almost surely, 2^{1940764638521} is an apocalyptic number.

It is an amenable number.

1940764638521 is a deficient number, since it is larger than the sum of its proper divisors (1).

1940764638521 is an equidigital number, since it uses as much as digits as its factorization.

1940764638521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8709120, while the sum is 56.

The spelling of 1940764638521 in words is "one trillion, nine hundred forty billion, seven hundred sixty-four million, six hundred thirty-eight thousand, five hundred twenty-one".