21019204536 has 256 divisors, whose sum is σ = 60914073600. Its totient is φ = 5985600000.

The previous prime is 21019204529. The next prime is 21019204571. The reversal of 21019204536 is 63540291012.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a junction number, because it is equal to n+sod(n) for n = 21019204497 and 21019204506.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 48768241 + ... + 48768671.

It is an arithmetic number, because the mean of its divisors is an integer number (237945600).

Almost surely, 2^21019204536 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 21019204536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30457036800).

21019204536 is an abundant number, since it is smaller than the sum of its proper divisors (39894869064).

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

21019204536 is a wasteful number, since it uses less digits than its factorization.

21019204536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 642 (or 638 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 33.

Adding to 21019204536 its reverse (63540291012), we get a palindrome (84559495548).

The spelling of 21019204536 in words is "twenty-one billion, nineteen million, two hundred four thousand, five hundred thirty-six".