128492621 has 4 divisors (see below), whose sum is σ = 128521692. Its totient is φ = 128463552.

The previous prime is 128492563. The next prime is 128492633. The reversal of 128492621 is 126294821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 126294821 = 1999 ⋅63179.

It can be written as a sum of positive squares in 2 ways, for example, as 97812100 + 30680521 = 9890^2 + 5539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-128492621 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128492641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6380 + ... + 17253.

It is an arithmetic number, because the mean of its divisors is an integer number (32130423).

Almost surely, 2^128492621 is an apocalyptic number.

It is an amenable number.

128492621 is a deficient number, since it is larger than the sum of its proper divisors (29071).

128492621 is an equidigital number, since it uses as much as digits as its factorization.

128492621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29070.

The product of its digits is 13824, while the sum is 35.

The square root of 128492621 is about 11335.4585703447. The cubic root of 128492621 is about 504.6141168711.

The spelling of 128492621 in words is "one hundred twenty-eight million, four hundred ninety-two thousand, six hundred twenty-one".