70128321 has 4 divisors (see below), whose sum is σ = 93504432. Its totient is φ = 46752212.

The previous prime is 70128319. The next prime is 70128329. The reversal of 70128321 is 12382107.

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.

It is a cyclic number.

It is not a de Polignac number, because 70128321 - 2¹ = 70128319 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 70128291 and 70128300.

It is not an unprimeable number, because it can be changed into a prime (70128329) 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, 11688051 + ... + 11688056.

It is an arithmetic number, because the mean of its divisors is an integer number (23376108).

Almost surely, 2^70128321 is an apocalyptic number.

It is an amenable number.

70128321 is a deficient number, since it is larger than the sum of its proper divisors (23376111).

70128321 is a wasteful number, since it uses less digits than its factorization.

70128321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23376110.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 70128321 is about 8374.2654006187. The cubic root of 70128321 is about 412.3802083743.

The spelling of 70128321 in words is "seventy million, one hundred twenty-eight thousand, three hundred twenty-one".