84121720551 has 36 divisors (see below), whose sum is σ = 141416127216. Its totient is φ = 47983858560.

The previous prime is 84121720457. The next prime is 84121720577. The reversal of 84121720551 is 15502712148.

It is a happy number.

84121720551 is a `hidden beast` number, since 84 + 1 + 2 + 1 + 7 + 20 + 551 = 666.

It is not a de Polignac number, because 84121720551 - 2¹⁰ = 84121719527 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84121720451) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 2253451 + ... + 2290476.

It is an arithmetic number, because the mean of its divisors is an integer number (3928225756).

Almost surely, 2^84121720551 is an apocalyptic number.

84121720551 is a deficient number, since it is larger than the sum of its proper divisors (57294406665).

84121720551 is a wasteful number, since it uses less digits than its factorization.

84121720551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4543972 (or 4543958 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The spelling of 84121720551 in words is "eighty-four billion, one hundred twenty-one million, seven hundred twenty thousand, five hundred fifty-one".