20618657493 has 8 divisors (see below), whose sum is σ = 31418906688. Its totient is φ = 11782089984.

The previous prime is 20618657491. The next prime is 20618657503. The reversal of 20618657493 is 39475681602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20618657493 - 2¹ = 20618657491 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20618657491) 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, 490920396 + ... + 490920437.

It is an arithmetic number, because the mean of its divisors is an integer number (3927363336).

It is a 1-persistent number, because it is pandigital, but 2⋅20618657493 = 41237314986 is not.

Almost surely, 2^20618657493 is an apocalyptic number.

It is an amenable number.

20618657493 is a deficient number, since it is larger than the sum of its proper divisors (10800249195).

20618657493 is an equidigital number, since it uses as much as digits as its factorization.

20618657493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 981840843.

The product of its (nonzero) digits is 2177280, while the sum is 51.

The spelling of 20618657493 in words is "twenty billion, six hundred eighteen million, six hundred fifty-seven thousand, four hundred ninety-three".