21213545100640 has 48 divisors (see below), whose sum is σ = 51339366177120. Its totient is φ = 8278456622080.

The previous prime is 21213545100613. The next prime is 21213545100641. The reversal of 21213545100640 is 4600154531212.

It is a junction number, because it is equal to n+sod(n) for n = 21213545100596 and 21213545100605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213545100641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1616879500 + ... + 1616892619.

It is an arithmetic number, because the mean of its divisors is an integer number (1069570128690).

Almost surely, 2^{21213545100640} is an apocalyptic number.

21213545100640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21213545100640 is an abundant number, since it is smaller than the sum of its proper divisors (30125821076480).

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

21213545100640 is a wasteful number, since it uses less digits than its factorization.

21213545100640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3233772175 (or 3233772167 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 34.

Adding to 21213545100640 its reverse (4600154531212), we get a palindrome (25813699631852).

The spelling of 21213545100640 in words is "twenty-one trillion, two hundred thirteen billion, five hundred forty-five million, one hundred thousand, six hundred forty".