21000233144 has 64 divisors (see below), whose sum is σ = 46057766400. Its totient is φ = 8870284800.

The previous prime is 21000233141. The next prime is 21000233147. The reversal of 21000233144 is 44133200012.

It is an interprime number because it is at equal distance from previous prime (21000233141) and next prime (21000233147).

It is a super-2 number, since 2×21000233144² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000233141) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 29339 + ... + 207029.

It is an arithmetic number, because the mean of its divisors is an integer number (719652600).

Almost surely, 2^21000233144 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21000233144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23028883200).

21000233144 is an abundant number, since it is smaller than the sum of its proper divisors (25057533256).

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

21000233144 is a wasteful number, since it uses less digits than its factorization.

21000233144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 177804 (or 177800 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

Adding to 21000233144 its reverse (44133200012), we get a palindrome (65133433156).

The spelling of 21000233144 in words is "twenty-one billion, two hundred thirty-three thousand, one hundred forty-four".