21661020450212 has 96 divisors (see below), whose sum is σ = 45014746896000. Its totient is φ = 8990557056000.

The previous prime is 21661020450193. The next prime is 21661020450263. The reversal of 21661020450212 is 21205402016612.

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, 65058539 + ... + 65390637.

It is an arithmetic number, because the mean of its divisors is an integer number (468903613500).

Almost surely, 2^{21661020450212} is an apocalyptic number.

21661020450212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21661020450212 is an abundant number, since it is smaller than the sum of its proper divisors (23353726445788).

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

21661020450212 is a wasteful number, since it uses less digits than its factorization.

21661020450212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 333357 (or 333355 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 32.

Adding to 21661020450212 its reverse (21205402016612), we get a palindrome (42866422466824).

The spelling of 21661020450212 in words is "twenty-one trillion, six hundred sixty-one billion, twenty million, four hundred fifty thousand, two hundred twelve".