72121647655 has 16 divisors (see below), whose sum is σ = 86829939360. Its totient is φ = 57508145152.

The previous prime is 72121647641. The next prime is 72121647691. The reversal of 72121647655 is 55674612127.

It is a cyclic number.

It is not a de Polignac number, because 72121647655 - 2¹⁷ = 72121516583 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5352687 + ... + 5366143.

It is an arithmetic number, because the mean of its divisors is an integer number (5426871210).

Almost surely, 2^72121647655 is an apocalyptic number.

72121647655 is a deficient number, since it is larger than the sum of its proper divisors (14708291705).

72121647655 is a wasteful number, since it uses less digits than its factorization.

72121647655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16898.

The product of its digits is 705600, while the sum is 46.

The spelling of 72121647655 in words is "seventy-two billion, one hundred twenty-one million, six hundred forty-seven thousand, six hundred fifty-five".