21001212101982 has 32 divisors (see below), whose sum is σ = 48002944276224. Its totient is φ = 6000324595200.

The previous prime is 21001212101941. The next prime is 21001212101983. The reversal of 21001212101982 is 28910121210012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001212101983) 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 15 ways as a sum of consecutive naturals, for example, 13553982 + ... + 15023742.

It is an arithmetic number, because the mean of its divisors is an integer number (1500092008632).

Almost surely, 2^{21001212101982} is an apocalyptic number.

21001212101982 is an abundant number, since it is smaller than the sum of its proper divisors (27001732174242).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21001212101982 is a wasteful number, since it uses less digits than its factorization.

21001212101982 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1809984.

The product of its (nonzero) digits is 1152, while the sum is 30.

Adding to 21001212101982 its reverse (28910121210012), we get a palindrome (49911333311994).

The spelling of 21001212101982 in words is "twenty-one trillion, one billion, two hundred twelve million, one hundred one thousand, nine hundred eighty-two".