72154240878721 has 4 divisors (see below), whose sum is σ = 76398607989252. Its totient is φ = 67909873768192.

The previous prime is 72154240878701. The next prime is 72154240878799. The reversal of 72154240878721 is 12787804245127.

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 42275171748096 + 29879069130625 = 6501936^2 + 5466175^2 .

It is a cyclic number.

It is not a de Polignac number, because 72154240878721 - 2¹³ = 72154240870529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72154240878701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2122183555240 + ... + 2122183555273.

It is an arithmetic number, because the mean of its divisors is an integer number (19099651997313).

Almost surely, 2^{72154240878721} is an apocalyptic number.

It is an amenable number.

72154240878721 is a deficient number, since it is larger than the sum of its proper divisors (4244367110531).

72154240878721 is a wasteful number, since it uses less digits than its factorization.

72154240878721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4244367110530.

The product of its (nonzero) digits is 14049280, while the sum is 58.

The spelling of 72154240878721 in words is "seventy-two trillion, one hundred fifty-four billion, two hundred forty million, eight hundred seventy-eight thousand, seven hundred twenty-one".