21129202764 has 36 divisors (see below), whose sum is σ = 54053429976. Its totient is φ = 6958210368.

The previous prime is 21129202741. The next prime is 21129202817. The reversal of 21129202764 is 46720292112.

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3532689 + ... + 3538664.

It is an arithmetic number, because the mean of its divisors is an integer number (1501484166).

Almost surely, 2^21129202764 is an apocalyptic number.

It is an amenable number.

21129202764 is an abundant number, since it is smaller than the sum of its proper divisors (32924227212).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21129202764 is a wasteful number, since it uses less digits than its factorization.

21129202764 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7071446 (or 7071441 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

Adding to 21129202764 its reverse (46720292112), we get a palindrome (67849494876).

The spelling of 21129202764 in words is "twenty-one billion, one hundred twenty-nine million, two hundred two thousand, seven hundred sixty-four".