21123133040 has 80 divisors (see below), whose sum is σ = 50189787648. Its totient is φ = 8264675328.

The previous prime is 21123133039. The next prime is 21123133099. The reversal of 21123133040 is 4033132112.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1421489 + ... + 1436271.

Almost surely, 2^21123133040 is an apocalyptic number.

21123133040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123133040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25094893824).

21123133040 is an abundant number, since it is smaller than the sum of its proper divisors (29066654608).

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

21123133040 is a wasteful number, since it uses less digits than its factorization.

21123133040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15186 (or 15180 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 21123133040 its reverse (4033132112), we get a palindrome (25156265152).

The spelling of 21123133040 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-three thousand, forty".