72102823121 has 4 divisors (see below), whose sum is σ = 82403226432. Its totient is φ = 61802419812.

The previous prime is 72102823099. The next prime is 72102823141. The reversal of 72102823121 is 12132820127.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12132820127 = 149 ⋅81428323.

It is not a de Polignac number, because 72102823121 - 2⁶ = 72102823057 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72102823141) 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, 5150201645 + ... + 5150201658.

It is an arithmetic number, because the mean of its divisors is an integer number (20600806608).

Almost surely, 2^72102823121 is an apocalyptic number.

It is an amenable number.

72102823121 is a deficient number, since it is larger than the sum of its proper divisors (10300403311).

72102823121 is a wasteful number, since it uses less digits than its factorization.

72102823121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10300403310.

The product of its (nonzero) digits is 2688, while the sum is 29.

The spelling of 72102823121 in words is "seventy-two billion, one hundred two million, eight hundred twenty-three thousand, one hundred twenty-one".