981661262138 has 4 divisors (see below), whose sum is σ = 1472491893210. Its totient is φ = 490830631068.

The previous prime is 981661262129. The next prime is 981661262173. The reversal of 981661262138 is 831262166189.

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., 751104755569 + 230556506569 = 866663^2 + 480163^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 981661262138.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245415315533 + ... + 245415315536.

Almost surely, 2^981661262138 is an apocalyptic number.

981661262138 is a deficient number, since it is larger than the sum of its proper divisors (490830631072).

981661262138 is a wasteful number, since it uses less digits than its factorization.

981661262138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490830631071.

The product of its digits is 1492992, while the sum is 53.

The spelling of 981661262138 in words is "nine hundred eighty-one billion, six hundred sixty-one million, two hundred sixty-two thousand, one hundred thirty-eight".