20039952581 has 4 divisors (see below), whose sum is σ = 21861766464. Its totient is φ = 18218138700.

The previous prime is 20039952577. The next prime is 20039952659. The reversal of 20039952581 is 18525993002.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20039952581 - 2² = 20039952577 is a prime.

It is a super-2 number, since 2×20039952581² (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 (20039952281) 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 3 ways as a sum of consecutive naturals, for example, 910906925 + ... + 910906946.

It is an arithmetic number, because the mean of its divisors is an integer number (5465441616).

Almost surely, 2^20039952581 is an apocalyptic number.

It is an amenable number.

20039952581 is a deficient number, since it is larger than the sum of its proper divisors (1821813883).

20039952581 is a wasteful number, since it uses less digits than its factorization.

20039952581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1821813882.

The product of its (nonzero) digits is 194400, while the sum is 44.

The spelling of 20039952581 in words is "twenty billion, thirty-nine million, nine hundred fifty-two thousand, five hundred eighty-one".