56578018661 has 2 divisors, whose sum is σ = 56578018662. Its totient is φ = 56578018660.

The previous prime is 56578018633. The next prime is 56578018681. The reversal of 56578018661 is 16681087565.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 32837064100 + 23740954561 = 181210^2 + 154081^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-56578018661 is a prime.

It is a super-3 number, since 3×56578018661³ (a number of 33 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56578018681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28289009330 + 28289009331.

It is an arithmetic number, because the mean of its divisors is an integer number (28289009331).

Almost surely, 2^56578018661 is an apocalyptic number.

It is an amenable number.

56578018661 is a deficient number, since it is larger than the sum of its proper divisors (1).

56578018661 is an equidigital number, since it uses as much as digits as its factorization.

56578018661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2419200, while the sum is 53.

The spelling of 56578018661 in words is "fifty-six billion, five hundred seventy-eight million, eighteen thousand, six hundred sixty-one".