128156401 has 4 divisors (see below), whose sum is σ = 128417904. Its totient is φ = 127894900.

The previous prime is 128156381. The next prime is 128156417. The reversal of 128156401 is 104651821.

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 a de Polignac number, because none of the positive numbers 2^k-128156401 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128156401.

It is not an unprimeable number, because it can be changed into a prime (128156701) 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, 130015 + ... + 130996.

It is an arithmetic number, because the mean of its divisors is an integer number (32104476).

Almost surely, 2^128156401 is an apocalyptic number.

It is an amenable number.

128156401 is a deficient number, since it is larger than the sum of its proper divisors (261503).

128156401 is an equidigital number, since it uses as much as digits as its factorization.

128156401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261502.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 128156401 is about 11320.6184018365. The cubic root of 128156401 is about 504.1735998622.

The spelling of 128156401 in words is "one hundred twenty-eight million, one hundred fifty-six thousand, four hundred one".