18834639021 has 16 divisors (see below), whose sum is σ = 30439821120. Its totient is φ = 11414932560.

The previous prime is 18834639001. The next prime is 18834639041. The reversal of 18834639021 is 12093643881.

18834639021 is a `hidden beast` number, since 1 + 8 + 8 + 3 + 4 + 639 + 0 + 2 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (18834639001) and next prime (18834639041).

It is not a de Polignac number, because 18834639021 - 2⁶ = 18834638957 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18834639001) 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, 31707850 + ... + 31708443.

It is an arithmetic number, because the mean of its divisors is an integer number (1902488820).

Almost surely, 2^18834639021 is an apocalyptic number.

18834639021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

18834639021 is a deficient number, since it is larger than the sum of its proper divisors (11605182099).

18834639021 is a wasteful number, since it uses less digits than its factorization.

18834639021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63416313 (or 63416307 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The spelling of 18834639021 in words is "eighteen billion, eight hundred thirty-four million, six hundred thirty-nine thousand, twenty-one".