128216531 has 2 divisors, whose sum is σ = 128216532. Its totient is φ = 128216530.

The previous prime is 128216509. The next prime is 128216603. The reversal of 128216531 is 135612821.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128216531 is a prime.

It is a super-2 number, since 2×128216531² = 32878957643347922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 128216494 and 128216503.

It is not a weakly prime, because it can be changed into another prime (128213531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64108265 + 64108266.

It is an arithmetic number, because the mean of its divisors is an integer number (64108266).

Almost surely, 2^128216531 is an apocalyptic number.

128216531 is a deficient number, since it is larger than the sum of its proper divisors (1).

128216531 is an equidigital number, since it uses as much as digits as its factorization.

128216531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 128216531 is about 11323.2738640377. The cubic root of 128216531 is about 504.2524389947.

The spelling of 128216531 in words is "one hundred twenty-eight million, two hundred sixteen thousand, five hundred thirty-one".