242137981 has 4 divisors (see below), whose sum is σ = 242999964. Its totient is φ = 241276000.

The previous prime is 242137969. The next prime is 242138003. The reversal of 242137981 is 189731242.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 189731242 = 2 ⋅94865621.

It can be written as a sum of positive squares in 2 ways, for example, as 209989081 + 32148900 = 14491^2 + 5670^2 .

It is a cyclic number.

It is not a de Polignac number, because 242137981 - 2¹⁹ = 241613693 is a prime.

It is a super-2 number, since 2×242137981² = 117261603685512722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 242137981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (242137081) 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, 430570 + ... + 431131.

It is an arithmetic number, because the mean of its divisors is an integer number (60749991).

Almost surely, 2^242137981 is an apocalyptic number.

It is an amenable number.

242137981 is a deficient number, since it is larger than the sum of its proper divisors (861983).

242137981 is an equidigital number, since it uses as much as digits as its factorization.

242137981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861982.

The product of its digits is 24192, while the sum is 37.

The square root of 242137981 is about 15560.7834314343. The cubic root of 242137981 is about 623.2863830410.

The spelling of 242137981 in words is "two hundred forty-two million, one hundred thirty-seven thousand, nine hundred eighty-one".