9945986075821 has 4 divisors (see below), whose sum is σ = 10469459027200. Its totient is φ = 9422513124444.

The previous prime is 9945986075819. The next prime is 9945986075827. The reversal of 9945986075821 is 1285706895499.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9945986075821 - 2¹ = 9945986075819 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9945986075827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 261736475661 + ... + 261736475698.

It is an arithmetic number, because the mean of its divisors is an integer number (2617364756800).

Almost surely, 2^{9945986075821} is an apocalyptic number.

It is an amenable number.

9945986075821 is a deficient number, since it is larger than the sum of its proper divisors (523472951379).

9945986075821 is a wasteful number, since it uses less digits than its factorization.

9945986075821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523472951378.

The product of its (nonzero) digits is 391910400, while the sum is 73.

The spelling of 9945986075821 in words is "nine trillion, nine hundred forty-five billion, nine hundred eighty-six million, seventy-five thousand, eight hundred twenty-one".