2391535438681 has 9 divisors (see below), whose sum is σ = 2395840779423. Its totient is φ = 2387237829120.

The previous prime is 2391535438673. The next prime is 2391535438739. The reversal of 2391535438681 is 1868345351932.

The square root of 2391535438681 is 1546459.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 935651878681 + 1455883560000 = 967291^2 + 1206600^2 .

It is not a de Polignac number, because 2391535438681 - 2³ = 2391535438673 is a prime.

It is a super-2 number, since 2×2391535438681² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2391535438381) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1189225966 + ... + 1189227976.

It is an arithmetic number, because the mean of its divisors is an integer number (266204531047).

Almost surely, 2^{2391535438681} is an apocalyptic number.

2391535438681 is the 1546459-th square number.

2391535438681 is the 773230-th centered octagonal number.

It is an amenable number.

2391535438681 is a deficient number, since it is larger than the sum of its proper divisors (4305340742).

2391535438681 is an frugal number, since it uses more digits than its factorization.

2391535438681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5560 (or 2780 counting only the distinct ones).

The product of its digits is 18662400, while the sum is 58.

The spelling of 2391535438681 in words is "two trillion, three hundred ninety-one billion, five hundred thirty-five million, four hundred thirty-eight thousand, six hundred eighty-one".