21212021985 has 32 divisors (see below), whose sum is σ = 42313853952. Its totient is φ = 8815385280.

The previous prime is 21212021959. The next prime is 21212022019. The reversal of 21212021985 is 58912021212.

It is not a de Polignac number, because 21212021985 - 2⁸ = 21212021729 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9181539 + ... + 9183848.

It is an arithmetic number, because the mean of its divisors is an integer number (1322307936).

Almost surely, 2^21212021985 is an apocalyptic number.

It is an amenable number.

21212021985 is a deficient number, since it is larger than the sum of its proper divisors (21101831967).

21212021985 is a wasteful number, since it uses less digits than its factorization.

21212021985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18365413.

The product of its (nonzero) digits is 5760, while the sum is 33.

The spelling of 21212021985 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, nine hundred eighty-five".