7128513381 has 16 divisors (see below), whose sum is σ = 10379672640. Its totient is φ = 4315758720.

The previous prime is 7128513377. The next prime is 7128513397. The reversal of 7128513381 is 1833158217.

It is not a de Polignac number, because 7128513381 - 2² = 7128513377 is a prime.

It is a super-2 number, since 2×7128513381² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7128513311) 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, 81886 + ... + 144783.

It is an arithmetic number, because the mean of its divisors is an integer number (648729540).

Almost surely, 2^7128513381 is an apocalyptic number.

It is an amenable number.

7128513381 is a deficient number, since it is larger than the sum of its proper divisors (3251159259).

7128513381 is a wasteful number, since it uses less digits than its factorization.

7128513381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 227636.

The product of its digits is 40320, while the sum is 39.

The square root of 7128513381 is about 84430.5239886618. The cubic root of 7128513381 is about 1924.5668002324.

It can be divided in two parts, 71285 and 13381, that added together give a triangular number (84666 = T₄₁₁).

The spelling of 7128513381 in words is "seven billion, one hundred twenty-eight million, five hundred thirteen thousand, three hundred eighty-one".