20645216421100 has 36 divisors (see below), whose sum is σ = 44800324486344. Its totient is φ = 8258048807680.

The previous prime is 20645216421079. The next prime is 20645216421161. The reversal of 20645216421100 is 112461254602.

It is a super-2 number, since 2×20645216421100² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 34117779 + ... + 34717621.

It is an arithmetic number, because the mean of its divisors is an integer number (1244453457954).

Almost surely, 2^{20645216421100} is an apocalyptic number.

20645216421100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20645216421100 is an abundant number, since it is smaller than the sum of its proper divisors (24155108065244).

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

20645216421100 is a wasteful number, since it uses less digits than its factorization.

20645216421100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 944034 (or 944027 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

Adding to 20645216421100 its reverse (112461254602), we get a palindrome (20757677675702).

The spelling of 20645216421100 in words is "twenty trillion, six hundred forty-five billion, two hundred sixteen million, four hundred twenty-one thousand, one hundred".