21767608742961 has 4 divisors (see below), whose sum is σ = 29023478323952. Its totient is φ = 14511739161972.

The previous prime is 21767608742881. The next prime is 21767608742963. The reversal of 21767608742961 is 16924780676712.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21767608742961 - 2⁹ = 21767608742449 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21767608742892 and 21767608742901.

It is not an unprimeable number, because it can be changed into a prime (21767608742963) 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, 3627934790491 + ... + 3627934790496.

It is an arithmetic number, because the mean of its divisors is an integer number (7255869580988).

Almost surely, 2^{21767608742961} is an apocalyptic number.

It is an amenable number.

21767608742961 is a deficient number, since it is larger than the sum of its proper divisors (7255869580991).

21767608742961 is an equidigital number, since it uses as much as digits as its factorization.

21767608742961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7255869580990.

The product of its (nonzero) digits is 85349376, while the sum is 66.

The spelling of 21767608742961 in words is "twenty-one trillion, seven hundred sixty-seven billion, six hundred eight million, seven hundred forty-two thousand, nine hundred sixty-one".