21100201520 has 20 divisors (see below), whose sum is σ = 49057968720. Its totient is φ = 8440080576.

The previous prime is 21100201487. The next prime is 21100201531. The reversal of 21100201520 is 2510200112.

It is a tau number, because it is divible by the number of its divisors (20).

It is a super-2 number, since 2×21100201520² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21100201495 and 21100201504.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131876180 + ... + 131876339.

It is an arithmetic number, because the mean of its divisors is an integer number (2452898436).

Almost surely, 2^21100201520 is an apocalyptic number.

21100201520 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100201520 is an abundant number, since it is smaller than the sum of its proper divisors (27957767200).

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

21100201520 is a wasteful number, since it uses less digits than its factorization.

21100201520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263752532 (or 263752526 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

Adding to 21100201520 its reverse (2510200112), we get a palindrome (23610401632).

The spelling of 21100201520 in words is "twenty-one billion, one hundred million, two hundred one thousand, five hundred twenty".