53997251981 has 4 divisors (see below), whose sum is σ = 53999107452. Its totient is φ = 53995396512.

The previous prime is 53997251969. The next prime is 53997252019. The reversal of 53997251981 is 18915279935.

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 20019703081 + 33977548900 = 141491^2 + 184330^2 .

It is a cyclic number.

It is not a de Polignac number, because 53997251981 - 2²⁶ = 53930143117 is a prime.

It is a super-2 number, since 2×53997251981² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 53997251981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53997251921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 883376 + ... + 942521.

It is an arithmetic number, because the mean of its divisors is an integer number (13499776863).

Almost surely, 2^53997251981 is an apocalyptic number.

It is an amenable number.

53997251981 is a deficient number, since it is larger than the sum of its proper divisors (1855471).

53997251981 is a wasteful number, since it uses less digits than its factorization.

53997251981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1855470.

The product of its digits is 6123600, while the sum is 59.

The spelling of 53997251981 in words is "fifty-three billion, nine hundred ninety-seven million, two hundred fifty-one thousand, nine hundred eighty-one".