55403891581 has 2 divisors, whose sum is σ = 55403891582. Its totient is φ = 55403891580.

The previous prime is 55403891533. The next prime is 55403891593. The reversal of 55403891581 is 18519830455.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 54720905625 + 682985956 = 233925^2 + 26134^2 .

It is a cyclic number.

It is not a de Polignac number, because 55403891581 - 2¹⁵ = 55403858813 is a prime.

It is a super-2 number, since 2×55403891581² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (55403891281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 27701945790 + 27701945791.

It is an arithmetic number, because the mean of its divisors is an integer number (27701945791).

Almost surely, 2^55403891581 is an apocalyptic number.

It is an amenable number.

55403891581 is a deficient number, since it is larger than the sum of its proper divisors (1).

55403891581 is an equidigital number, since it uses as much as digits as its factorization.

55403891581 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864000, while the sum is 49.

The spelling of 55403891581 in words is "fifty-five billion, four hundred three million, eight hundred ninety-one thousand, five hundred eighty-one".