61866437583381 has 4 divisors (see below), whose sum is σ = 82488583444512. Its totient is φ = 41244291722252.

The previous prime is 61866437583287. The next prime is 61866437583389. The reversal of 61866437583381 is 18338573466816.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61866437583381 - 2⁷ = 61866437583253 is a prime.

It is a super-2 number, since 2×61866437583381² (a number of 28 digits) contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61866437583389) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10311072930561 + ... + 10311072930566.

It is an arithmetic number, because the mean of its divisors is an integer number (20622145861128).

Almost surely, 2^{61866437583381} is an apocalyptic number.

It is an amenable number.

61866437583381 is a deficient number, since it is larger than the sum of its proper divisors (20622145861131).

61866437583381 is a wasteful number, since it uses less digits than its factorization.

61866437583381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20622145861130.

The product of its digits is 418037760, while the sum is 69.

The spelling of 61866437583381 in words is "sixty-one trillion, eight hundred sixty-six billion, four hundred thirty-seven million, five hundred eighty-three thousand, three hundred eighty-one".