21669767864 has 8 divisors (see below), whose sum is σ = 40630814760. Its totient is φ = 10834883928.

The previous prime is 21669767851. The next prime is 21669767879. The reversal of 21669767864 is 46876796612.

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 21669767797 and 21669767806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1354360484 + ... + 1354360499.

It is an arithmetic number, because the mean of its divisors is an integer number (5078851845).

Almost surely, 2^21669767864 is an apocalyptic number.

It is an amenable number.

21669767864 is a deficient number, since it is larger than the sum of its proper divisors (18961046896).

21669767864 is a wasteful number, since it uses less digits than its factorization.

21669767864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2708720989 (or 2708720985 counting only the distinct ones).

The product of its digits is 36578304, while the sum is 62.

The spelling of 21669767864 in words is "twenty-one billion, six hundred sixty-nine million, seven hundred sixty-seven thousand, eight hundred sixty-four".