21777694336513 has 4 divisors (see below), whose sum is σ = 21777783677140. Its totient is φ = 21777604995888.

The previous prime is 21777694336469. The next prime is 21777694336547. The reversal of 21777694336513 is 31563349677712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17046229749264 + 4731464587249 = 4128708^2 + 2175193^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21777694336513 is a prime.

It is a super-2 number, since 2×21777694336513² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21777694336553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44303670 + ... + 44792527.

It is an arithmetic number, because the mean of its divisors is an integer number (5444445919285).

Almost surely, 2^{21777694336513} is an apocalyptic number.

It is an amenable number.

21777694336513 is a deficient number, since it is larger than the sum of its proper divisors (89340627).

21777694336513 is an equidigital number, since it uses as much as digits as its factorization.

21777694336513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89340626.

The product of its digits is 120022560, while the sum is 64.

The spelling of 21777694336513 in words is "twenty-one trillion, seven hundred seventy-seven billion, six hundred ninety-four million, three hundred thirty-six thousand, five hundred thirteen".