21006459552 has 192 divisors, whose sum is σ = 61056809856. Its totient is φ = 6282608640.

The previous prime is 21006459541. The next prime is 21006459557. The reversal of 21006459552 is 25595460012.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a self number, because there is not a number n which added to its sum of digits gives 21006459552.

It is not an unprimeable number, because it can be changed into a prime (21006459557) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 18061723 + ... + 18062885.

It is an arithmetic number, because the mean of its divisors is an integer number (318004218).

Almost surely, 2^21006459552 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 21006459552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30528404928).

21006459552 is an abundant number, since it is smaller than the sum of its proper divisors (40050350304).

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

21006459552 is a wasteful number, since it uses less digits than its factorization.

21006459552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1583 (or 1575 counting only the distinct ones).

The product of its (nonzero) digits is 108000, while the sum is 39.

The spelling of 21006459552 in words is "twenty-one billion, six million, four hundred fifty-nine thousand, five hundred fifty-two".