20390742593 has 8 divisors (see below), whose sum is σ = 22260074088. Its totient is φ = 18564384384.

The previous prime is 20390742527. The next prime is 20390742611. The reversal of 20390742593 is 39524709302.

It can be written as a sum of positive squares in 4 ways, for example, as 760490929 + 19630251664 = 27577^2 + 140108^2 .

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

It is not a de Polignac number, because 20390742593 - 2²⁴ = 20373965377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20390742793) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10742330 + ... + 10744227.

It is an arithmetic number, because the mean of its divisors is an integer number (2782509261).

Almost surely, 2^20390742593 is an apocalyptic number.

It is an amenable number.

20390742593 is a deficient number, since it is larger than the sum of its proper divisors (1869331495).

20390742593 is a wasteful number, since it uses less digits than its factorization.

20390742593 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21486643.

The product of its (nonzero) digits is 408240, while the sum is 44.

The spelling of 20390742593 in words is "twenty billion, three hundred ninety million, seven hundred forty-two thousand, five hundred ninety-three".