18949294981 has 4 divisors (see below), whose sum is σ = 19058828652. Its totient is φ = 18839761312.

The previous prime is 18949294979. The next prime is 18949295047.

It is a happy number.

18949294981 is nontrivially palindromic in base 10.

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 13255837956 + 5693457025 = 115134^2 + 75455^2 .

It is a cyclic number.

It is not a de Polignac number, because 18949294981 - 2¹ = 18949294979 is a prime.

It is a super-2 number, since 2×18949294981² (a number of 21 digits) contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18949294181) 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, 54766576 + ... + 54766921.

It is an arithmetic number, because the mean of its divisors is an integer number (4764707163).

Almost surely, 2^18949294981 is an apocalyptic number.

It is an amenable number.

18949294981 is a deficient number, since it is larger than the sum of its proper divisors (109533671).

18949294981 is a wasteful number, since it uses less digits than its factorization.

18949294981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109533670.

The product of its digits is 13436928, while the sum is 64.

The spelling of 18949294981 in words is "eighteen billion, nine hundred forty-nine million, two hundred ninety-four thousand, nine hundred eighty-one".