52991981 has 12 divisors (see below), whose sum is σ = 62657820. Its totient is φ = 44674560.

The previous prime is 52991951. The next prime is 52991987. The reversal of 52991981 is 18919925.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 15476356 + 37515625 = 3934^2 + 6125^2 .

It is not a de Polignac number, because 52991981 - 2¹⁴ = 52975597 is a prime.

It is a super-2 number, since 2×52991981² = 5616300100608722, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (52991987) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5876 + ... + 11853.

It is an arithmetic number, because the mean of its divisors is an integer number (5221485).

Almost surely, 2^52991981 is an apocalyptic number.

It is an amenable number.

52991981 is a deficient number, since it is larger than the sum of its proper divisors (9665839).

52991981 is a wasteful number, since it uses less digits than its factorization.

52991981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17804 (or 17797 counting only the distinct ones).

The product of its digits is 58320, while the sum is 44.

The square root of 52991981 is about 7279.5591212655. The cubic root of 52991981 is about 375.6096300292.

The spelling of 52991981 in words is "fifty-two million, nine hundred ninety-one thousand, nine hundred eighty-one".