128520631 has 2 divisors, whose sum is σ = 128520632. Its totient is φ = 128520630.

The previous prime is 128520611. The next prime is 128520643. The reversal of 128520631 is 136025821.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 128520631 - 2¹¹ = 128518583 is a prime.

It is a super-2 number, since 2×128520631² = 33035105185276322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 128520631.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128520611) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64260315 + 64260316.

It is an arithmetic number, because the mean of its divisors is an integer number (64260316).

Almost surely, 2^128520631 is an apocalyptic number.

128520631 is a deficient number, since it is larger than the sum of its proper divisors (1).

128520631 is an equidigital number, since it uses as much as digits as its factorization.

128520631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 128520631 is about 11336.6940066317. The cubic root of 128520631 is about 504.6507810116.

The spelling of 128520631 in words is "one hundred twenty-eight million, five hundred twenty thousand, six hundred thirty-one".