21769587757 has 2 divisors, whose sum is σ = 21769587758. Its totient is φ = 21769587756.

The previous prime is 21769587751. The next prime is 21769587787. The reversal of 21769587757 is 75778596712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13938399721 + 7831188036 = 118061^2 + 88494^2 .

It is a cyclic number.

It is not a de Polignac number, because 21769587757 - 2⁷ = 21769587629 is a prime.

It is a super-2 number, since 2×21769587757² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21769587751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10884793878 + 10884793879.

It is an arithmetic number, because the mean of its divisors is an integer number (10884793879).

Almost surely, 2^21769587757 is an apocalyptic number.

It is an amenable number.

21769587757 is a deficient number, since it is larger than the sum of its proper divisors (1).

21769587757 is an equidigital number, since it uses as much as digits as its factorization.

21769587757 is an evil number, because the sum of its binary digits is even.

The product of its digits is 51861600, while the sum is 64.

The spelling of 21769587757 in words is "twenty-one billion, seven hundred sixty-nine million, five hundred eighty-seven thousand, seven hundred fifty-seven".