61812591 has 4 divisors (see below), whose sum is σ = 82416792. Its totient is φ = 41208392.

The previous prime is 61812563. The next prime is 61812593. The reversal of 61812591 is 19521816.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 61812591 - 2¹⁰ = 61811567 is a prime.

It is a super-2 number, since 2×61812591² = 7641592812266562, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61812593) 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, 10302096 + ... + 10302101.

It is an arithmetic number, because the mean of its divisors is an integer number (20604198).

Almost surely, 2^61812591 is an apocalyptic number.

61812591 is a deficient number, since it is larger than the sum of its proper divisors (20604201).

61812591 is a wasteful number, since it uses less digits than its factorization.

61812591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20604200.

The product of its digits is 4320, while the sum is 33.

The square root of 61812591 is about 7862.0983840194. The cubic root of 61812591 is about 395.3899711134.

The spelling of 61812591 in words is "sixty-one million, eight hundred twelve thousand, five hundred ninety-one".