21135747667 has 2 divisors, whose sum is σ = 21135747668. Its totient is φ = 21135747666.

The previous prime is 21135747643. The next prime is 21135747697. The reversal of 21135747667 is 76674753112.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21135747667 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21135747667.

It is not a weakly prime, because it can be changed into another prime (21135747697) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10567873833 + 10567873834.

It is an arithmetic number, because the mean of its divisors is an integer number (10567873834).

Almost surely, 2^21135747667 is an apocalyptic number.

21135747667 is a deficient number, since it is larger than the sum of its proper divisors (1).

21135747667 is an equidigital number, since it uses as much as digits as its factorization.

21135747667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1481760, while the sum is 49.

The spelling of 21135747667 in words is "twenty-one billion, one hundred thirty-five million, seven hundred forty-seven thousand, six hundred sixty-seven".