53381981 has 4 divisors (see below), whose sum is σ = 53411964. Its totient is φ = 53352000.

The previous prime is 53381957. The next prime is 53382013. The reversal of 53381981 is 18918335.

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 8357881 + 45024100 = 2891^2 + 6710^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-53381981 is a prime.

It is a super-2 number, since 2×53381981² = 5699271790968722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53381281) 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, 12140 + ... + 15941.

It is an arithmetic number, because the mean of its divisors is an integer number (13352991).

Almost surely, 2^53381981 is an apocalyptic number.

It is an amenable number.

53381981 is a deficient number, since it is larger than the sum of its proper divisors (29983).

53381981 is a wasteful number, since it uses less digits than its factorization.

53381981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29982.

The product of its digits is 25920, while the sum is 38.

The square root of 53381981 is about 7306.2973522845. The cubic root of 53381981 is about 376.5288247900.

The spelling of 53381981 in words is "fifty-three million, three hundred eighty-one thousand, nine hundred eighty-one".