20491167939 has 16 divisors (see below), whose sum is σ = 29812333824. Its totient is φ = 12415973600.

The previous prime is 20491167883. The next prime is 20491168157. The reversal of 20491167939 is 93976119402.

It is a cyclic number.

It is not a de Polignac number, because 20491167939 - 2¹⁶ = 20491102403 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20491167891 and 20491167900.

It is not an unprimeable number, because it can be changed into a prime (20491163939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74197 + ... + 215609.

It is an arithmetic number, because the mean of its divisors is an integer number (1863270864).

Almost surely, 2^20491167939 is an apocalyptic number.

20491167939 is a deficient number, since it is larger than the sum of its proper divisors (9321165885).

20491167939 is a wasteful number, since it uses less digits than its factorization.

20491167939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145818.

The product of its (nonzero) digits is 734832, while the sum is 51.

The spelling of 20491167939 in words is "twenty billion, four hundred ninety-one million, one hundred sixty-seven thousand, nine hundred thirty-nine".