9947121845 has 16 divisors (see below), whose sum is σ = 12217732032. Its totient is φ = 7770349440.

The previous prime is 9947121823. The next prime is 9947121871. The reversal of 9947121845 is 5481217499.

It is a happy number.

It is not a de Polignac number, because 9947121845 - 2²⁶ = 9880012981 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 9947121793 and 9947121802.

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, 1450625 + ... + 1457465.

It is an arithmetic number, because the mean of its divisors is an integer number (763608252).

Almost surely, 2^9947121845 is an apocalyptic number.

It is an amenable number.

9947121845 is a deficient number, since it is larger than the sum of its proper divisors (2270610187).

9947121845 is a wasteful number, since it uses less digits than its factorization.

9947121845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13652.

The product of its digits is 725760, while the sum is 50.

The square root of 9947121845 is about 99735.2587854466. The cubic root of 9947121845 is about 2150.6305592354.

The spelling of 9947121845 in words is "nine billion, nine hundred forty-seven million, one hundred twenty-one thousand, eight hundred forty-five".