53815981 has 2 divisors, whose sum is σ = 53815982. Its totient is φ = 53815980.

The previous prime is 53815973. The next prime is 53815991. The reversal of 53815981 is 18951835.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 45778756 + 8037225 = 6766^2 + 2835^2 .

It is a cyclic number.

It is not a de Polignac number, because 53815981 - 2³ = 53815973 is a prime.

It is a super-2 number, since 2×53815981² = 5792319621984722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (53815901) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26907990 + 26907991.

It is an arithmetic number, because the mean of its divisors is an integer number (26907991).

Almost surely, 2^53815981 is an apocalyptic number.

It is an amenable number.

53815981 is a deficient number, since it is larger than the sum of its proper divisors (1).

53815981 is an equidigital number, since it uses as much as digits as its factorization.

53815981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 43200, while the sum is 40.

The square root of 53815981 is about 7335.9376360490. The cubic root of 53815981 is about 377.5464755726.

The spelling of 53815981 in words is "fifty-three million, eight hundred fifteen thousand, nine hundred eighty-one".