84721557 has 16 divisors (see below), whose sum is σ = 123733440. Its totient is φ = 51324672.

The previous prime is 84721547. The next prime is 84721577. The reversal of 84721557 is 75512748.

It is not a de Polignac number, because 84721557 - 2⁴ = 84721541 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (84721547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27163 + ... + 30120.

It is an arithmetic number, because the mean of its divisors is an integer number (7733340).

Almost surely, 2^84721557 is an apocalyptic number.

84721557 is a gapful number since it is divisible by the number (87) formed by its first and last digit.

It is an amenable number.

84721557 is a deficient number, since it is larger than the sum of its proper divisors (39011883).

84721557 is a wasteful number, since it uses less digits than its factorization.

84721557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57332.

The product of its digits is 78400, while the sum is 39.

The square root of 84721557 is about 9204.4313784177. The cubic root of 84721557 is about 439.2023375296.

The spelling of 84721557 in words is "eighty-four million, seven hundred twenty-one thousand, five hundred fifty-seven".