55081581 has 16 divisors (see below), whose sum is σ = 79573824. Its totient is φ = 33755904.

The previous prime is 55081577. The next prime is 55081583. The reversal of 55081581 is 18518055.

It is not a de Polignac number, because 55081581 - 2² = 55081577 is a prime.

It is a super-2 number, since 2×55081581² = 6067961130919122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (55081583) 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, 10366 + ... + 14751.

It is an arithmetic number, because the mean of its divisors is an integer number (4973364).

Almost surely, 2^55081581 is an apocalyptic number.

55081581 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

55081581 is a deficient number, since it is larger than the sum of its proper divisors (24492243).

55081581 is a wasteful number, since it uses less digits than its factorization.

55081581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25180.

The product of its (nonzero) digits is 8000, while the sum is 33.

The square root of 55081581 is about 7421.6966389095. The cubic root of 55081581 is about 380.4831826790.

The spelling of 55081581 in words is "fifty-five million, eighty-one thousand, five hundred eighty-one".