128692381 has 2 divisors, whose sum is σ = 128692382. Its totient is φ = 128692380.

The previous prime is 128692331. The next prime is 128692409. The reversal of 128692381 is 183296821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121749156 + 6943225 = 11034^2 + 2635^2 .

It is a cyclic number.

It is not a de Polignac number, because 128692381 - 2¹¹ = 128690333 is a prime.

It is a super-2 number, since 2×128692381² = 33123457854898322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (128692331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 64346190 + 64346191.

It is an arithmetic number, because the mean of its divisors is an integer number (64346191).

Almost surely, 2^128692381 is an apocalyptic number.

It is an amenable number.

128692381 is a deficient number, since it is larger than the sum of its proper divisors (1).

128692381 is an equidigital number, since it uses as much as digits as its factorization.

128692381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 41472, while the sum is 40.

The square root of 128692381 is about 11344.2664372801. The cubic root of 128692381 is about 504.8754795430.

The spelling of 128692381 in words is "one hundred twenty-eight million, six hundred ninety-two thousand, three hundred eighty-one".