20485256381 has 4 divisors (see below), whose sum is σ = 20589242652. Its totient is φ = 20381270112.

The previous prime is 20485256369. The next prime is 20485256447. The reversal of 20485256381 is 18365258402.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19646227225 + 839029156 = 140165^2 + 28966^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20485256381 is a prime.

It is a super-2 number, since 2×20485256381² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20485250381) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51992840 + ... + 51993233.

It is an arithmetic number, because the mean of its divisors is an integer number (5147310663).

Almost surely, 2^20485256381 is an apocalyptic number.

It is an amenable number.

20485256381 is a deficient number, since it is larger than the sum of its proper divisors (103986271).

20485256381 is a wasteful number, since it uses less digits than its factorization.

20485256381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103986270.

The product of its (nonzero) digits is 460800, while the sum is 44.

The spelling of 20485256381 in words is "twenty billion, four hundred eighty-five million, two hundred fifty-six thousand, three hundred eighty-one".