20215181738 has 4 divisors (see below), whose sum is σ = 30322772610. Its totient is φ = 10107590868.

The previous prime is 20215181737. The next prime is 20215181761. The reversal of 20215181738 is 83718151202.

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

It can be written as a sum of positive squares in only one way, i.e., 18669669769 + 1545511969 = 136637^2 + 39313^2 .

It is not an unprimeable number, because it can be changed into a prime (20215181737) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5053795433 + ... + 5053795436.

Almost surely, 2^20215181738 is an apocalyptic number.

20215181738 is a deficient number, since it is larger than the sum of its proper divisors (10107590872).

20215181738 is a wasteful number, since it uses less digits than its factorization.

20215181738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10107590871.

The product of its (nonzero) digits is 26880, while the sum is 38.

The spelling of 20215181738 in words is "twenty billion, two hundred fifteen million, one hundred eighty-one thousand, seven hundred thirty-eight".