21146004552 has 64 divisors (see below), whose sum is σ = 55837656000. Its totient is φ = 6654852864.

The previous prime is 21146004493. The next prime is 21146004553. The reversal of 21146004552 is 25540064112.

It is not an unprimeable number, because it can be changed into a prime (21146004553) 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, 54474 + ... + 212742.

It is an arithmetic number, because the mean of its divisors is an integer number (872463375).

Almost surely, 2^21146004552 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 21146004552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27918828000).

21146004552 is an abundant number, since it is smaller than the sum of its proper divisors (34691651448).

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

21146004552 is a wasteful number, since it uses less digits than its factorization.

21146004552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158590 (or 158586 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

Adding to 21146004552 its reverse (25540064112), we get a palindrome (46686068664).

The spelling of 21146004552 in words is "twenty-one billion, one hundred forty-six million, four thousand, five hundred fifty-two".