5515851981 has 16 divisors (see below), whose sum is σ = 7743496640. Its totient is φ = 3482818560.

The previous prime is 5515851959. The next prime is 5515851989. The reversal of 5515851981 is 1891585155.

It is not a de Polignac number, because 5515851981 - 2⁵ = 5515851949 is a prime.

It is a super-2 number, since 2×5515851981² = 60849246152603248722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 5515851981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5515851989) 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, 274911 + ... + 294291.

It is an arithmetic number, because the mean of its divisors is an integer number (483968540).

Almost surely, 2^5515851981 is an apocalyptic number.

It is an amenable number.

5515851981 is a deficient number, since it is larger than the sum of its proper divisors (2227644659).

5515851981 is a wasteful number, since it uses less digits than its factorization.

5515851981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24396.

The product of its digits is 360000, while the sum is 48.

The square root of 5515851981 is about 74268.7820083243. The cubic root of 5515851981 is about 1766.8683899518.

The spelling of 5515851981 in words is "five billion, five hundred fifteen million, eight hundred fifty-one thousand, nine hundred eighty-one".