82128901 has 4 divisors (see below), whose sum is σ = 82250892. Its totient is φ = 82006912.

The previous prime is 82128859. The next prime is 82128923. The reversal of 82128901 is 10982128.

82128901 = T₇₃₉₈ + T₇₃₉₉ + T₇₄₀₀.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 75238276 + 6890625 = 8674^2 + 2625^2 .

It is a cyclic number.

It is not a de Polignac number, because 82128901 - 2¹⁹ = 81604613 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82128941) 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, 59980 + ... + 61333.

It is an arithmetic number, because the mean of its divisors is an integer number (20562723).

Almost surely, 2^82128901 is an apocalyptic number.

82128901 is the 7400-th centered triangular number.

It is an amenable number.

82128901 is a deficient number, since it is larger than the sum of its proper divisors (121991).

82128901 is a wasteful number, since it uses less digits than its factorization.

82128901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121990.

The product of its (nonzero) digits is 2304, while the sum is 31.

The square root of 82128901 is about 9062.4997103448. The cubic root of 82128901 is about 434.6756749291.

The spelling of 82128901 in words is "eighty-two million, one hundred twenty-eight thousand, nine hundred one".