21129749790 has 32 divisors (see below), whose sum is σ = 51890737536. Its totient is φ = 5503562400.

The previous prime is 21129749783. The next prime is 21129749807. The reversal of 21129749790 is 9794792112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8188536 + ... + 8191115.

It is an arithmetic number, because the mean of its divisors is an integer number (1621585548).

Almost surely, 2^21129749790 is an apocalyptic number.

21129749790 is an abundant number, since it is smaller than the sum of its proper divisors (30760987746).

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

21129749790 is a wasteful number, since it uses less digits than its factorization.

21129749790 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16379704.

The product of its (nonzero) digits is 571536, while the sum is 51.

The spelling of 21129749790 in words is "twenty-one billion, one hundred twenty-nine million, seven hundred forty-nine thousand, seven hundred ninety".