2051691721908 has 24 divisors (see below), whose sum is σ = 4789436208480. Its totient is φ = 683589308640.

The previous prime is 2051691721901. The next prime is 2051691721909. The reversal of 2051691721908 is 8091271961502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2051691721901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38463738 + ... + 38517041.

It is an arithmetic number, because the mean of its divisors is an integer number (199559842020).

Almost surely, 2^{2051691721908} is an apocalyptic number.

It is an amenable number.

2051691721908 is an abundant number, since it is smaller than the sum of its proper divisors (2737744486572).

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

2051691721908 is a wasteful number, since it uses less digits than its factorization.

2051691721908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76983007 (or 76983005 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 51.

The spelling of 2051691721908 in words is "two trillion, fifty-one billion, six hundred ninety-one million, seven hundred twenty-one thousand, nine hundred eight".