21947784111967 has 16 divisors (see below), whose sum is σ = 26289057894912. Its totient is φ = 17915185775520.

The previous prime is 21947784111943. The next prime is 21947784111973. The reversal of 21947784111967 is 76911148774912.

It is a cyclic number.

It is not a de Polignac number, because 21947784111967 - 2⁷ = 21947784111839 is a prime.

It is a super-2 number, since 2×21947784111967² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21947784112967) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 300231384 + ... + 300304477.

It is an arithmetic number, because the mean of its divisors is an integer number (1643066118432).

Almost surely, 2^{21947784111967} is an apocalyptic number.

21947784111967 is a deficient number, since it is larger than the sum of its proper divisors (4341273782945).

21947784111967 is a wasteful number, since it uses less digits than its factorization.

21947784111967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 600536118.

The product of its digits is 42674688, while the sum is 67.

The spelling of 21947784111967 in words is "twenty-one trillion, nine hundred forty-seven billion, seven hundred eighty-four million, one hundred eleven thousand, nine hundred sixty-seven".