20138805591 has 16 divisors (see below), whose sum is σ = 29199669984. Its totient is φ = 12294595584.

The previous prime is 20138805571. The next prime is 20138805601. The reversal of 20138805591 is 19550883102.

It is not a de Polignac number, because 20138805591 - 2⁹ = 20138805079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20138805551) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5334310 + ... + 5338083.

It is an arithmetic number, because the mean of its divisors is an integer number (1824979374).

Almost surely, 2^20138805591 is an apocalyptic number.

20138805591 is a deficient number, since it is larger than the sum of its proper divisors (9060864393).

20138805591 is a wasteful number, since it uses less digits than its factorization.

20138805591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10672450.

The product of its (nonzero) digits is 86400, while the sum is 42.

The spelling of 20138805591 in words is "twenty billion, one hundred thirty-eight million, eight hundred five thousand, five hundred ninety-one".