53681991 has 16 divisors (see below), whose sum is σ = 78278400. Its totient is φ = 32453120.

The previous prime is 53681963. The next prime is 53682019. The reversal of 53681991 is 19918635.

It is an interprime number because it is at equal distance from previous prime (53681963) and next prime (53682019).

It is a cyclic number.

It is not a de Polignac number, because 53681991 - 2¹⁰ = 53680967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53681591) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13006 + ... + 16628.

It is an arithmetic number, because the mean of its divisors is an integer number (4892400).

Almost surely, 2^53681991 is an apocalyptic number.

53681991 is a deficient number, since it is larger than the sum of its proper divisors (24596409).

53681991 is a wasteful number, since it uses less digits than its factorization.

53681991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4086.

The product of its digits is 58320, while the sum is 42.

The square root of 53681991 is about 7326.7995059234. The cubic root of 53681991 is about 377.2328791689.

The spelling of 53681991 in words is "fifty-three million, six hundred eighty-one thousand, nine hundred ninety-one".