20205887818 has 4 divisors (see below), whose sum is σ = 30308831730. Its totient is φ = 10102943908.

The previous prime is 20205887789. The next prime is 20205887827. The reversal of 20205887818 is 81878850202.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81878850202 = 2 ⋅40939425101.

It can be written as a sum of positive squares in only one way, i.e., 16887782209 + 3318105609 = 129953^2 + 57603^2 .

It is a super-2 number, since 2×20205887818² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5051471953 + ... + 5051471956.

Almost surely, 2^20205887818 is an apocalyptic number.

20205887818 is a deficient number, since it is larger than the sum of its proper divisors (10102943912).

20205887818 is a wasteful number, since it uses less digits than its factorization.

20205887818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10102943911.

The product of its (nonzero) digits is 573440, while the sum is 49.

The spelling of 20205887818 in words is "twenty billion, two hundred five million, eight hundred eighty-seven thousand, eight hundred eighteen".