128420997 has 8 divisors (see below), whose sum is σ = 172743744. Its totient is φ = 84856128.

The previous prime is 128420989. The next prime is 128421001. The reversal of 128420997 is 799024821.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128420997 - 2³ = 128420989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128420917) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 189073 + ... + 189750.

It is an arithmetic number, because the mean of its divisors is an integer number (21592968).

Almost surely, 2^128420997 is an apocalyptic number.

It is an amenable number.

128420997 is a deficient number, since it is larger than the sum of its proper divisors (44322747).

128420997 is a wasteful number, since it uses less digits than its factorization.

128420997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 378939.

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 128420997 is about 11332.2988400412. The cubic root of 128420997 is about 504.5203392446.

The spelling of 128420997 in words is "one hundred twenty-eight million, four hundred twenty thousand, nine hundred ninety-seven".