21428767736 has 8 divisors (see below), whose sum is σ = 40178939520. Its totient is φ = 10714383864.

The previous prime is 21428767729. The next prime is 21428767747. The reversal of 21428767736 is 63776782412.

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

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, 1339297976 + ... + 1339297991.

It is an arithmetic number, because the mean of its divisors is an integer number (5022367440).

Almost surely, 2^21428767736 is an apocalyptic number.

It is an amenable number.

21428767736 is a deficient number, since it is larger than the sum of its proper divisors (18750171784).

21428767736 is a wasteful number, since it uses less digits than its factorization.

21428767736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2678595973 (or 2678595969 counting only the distinct ones).

The product of its digits is 4741632, while the sum is 53.

The spelling of 21428767736 in words is "twenty-one billion, four hundred twenty-eight million, seven hundred sixty-seven thousand, seven hundred thirty-six".