21203123100 has 36 divisors (see below), whose sum is σ = 61347703704. Its totient is φ = 5654166080.

The previous prime is 21203123099. The next prime is 21203123107. The reversal of 21203123100 is 132130212.

It is a super-2 number, since 2×21203123100² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21203123100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21203123107) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35338239 + ... + 35338838.

Almost surely, 2^21203123100 is an apocalyptic number.

21203123100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21203123100 is an abundant number, since it is smaller than the sum of its proper divisors (40144580604).

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

21203123100 is a wasteful number, since it uses less digits than its factorization.

21203123100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70677094 (or 70677087 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 21203123100 its reverse (132130212), we get a palindrome (21335253312).

The spelling of 21203123100 in words is "twenty-one billion, two hundred three million, one hundred twenty-three thousand, one hundred".