124991672821 has 4 divisors (see below), whose sum is σ = 125349815500. Its totient is φ = 124633530144.

The previous prime is 124991672809. The next prime is 124991672833. The reversal of 124991672821 is 128276199421.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 128276199421 = 6679 ⋅19205899.

It is an interprime number because it is at equal distance from previous prime (124991672809) and next prime (124991672833).

It can be written as a sum of positive squares in 2 ways, for example, as 108429269796 + 16562403025 = 329286^2 + 128695^2 .

It is a cyclic number.

It is not a de Polignac number, because 124991672821 - 2¹¹ = 124991670773 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 (124991672801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 179070816 + ... + 179071513.

It is an arithmetic number, because the mean of its divisors is an integer number (31337453875).

Almost surely, 2^124991672821 is an apocalyptic number.

It is an amenable number.

124991672821 is a deficient number, since it is larger than the sum of its proper divisors (358142679).

124991672821 is an equidigital number, since it uses as much as digits as its factorization.

124991672821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 358142678.

The product of its digits is 870912, while the sum is 52.

The spelling of 124991672821 in words is "one hundred twenty-four billion, nine hundred ninety-one million, six hundred seventy-two thousand, eight hundred twenty-one".