70128581 has 4 divisors (see below), whose sum is σ = 70173312. Its totient is φ = 70083852.

The previous prime is 70128551. The next prime is 70128613. The reversal of 70128581 is 18582107.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 18582107 = 1481 ⋅12547.

It is a cyclic number.

It is not a de Polignac number, because 70128581 - 2¹⁰ = 70127557 is a prime.

It is a super-2 number, since 2×70128581² = 9836035746147122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (70128551) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19925 + ... + 23178.

It is an arithmetic number, because the mean of its divisors is an integer number (17543328).

Almost surely, 2^70128581 is an apocalyptic number.

It is an amenable number.

70128581 is a deficient number, since it is larger than the sum of its proper divisors (44731).

70128581 is a wasteful number, since it uses less digits than its factorization.

70128581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44730.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 70128581 is about 8374.2809243540. The cubic root of 70128581 is about 412.3807180054.

The spelling of 70128581 in words is "seventy million, one hundred twenty-eight thousand, five hundred eighty-one".