21007371528 has 192 divisors, whose sum is σ = 67129171200. Its totient is φ = 5850915840.

The previous prime is 21007371523. The next prime is 21007371533. The reversal of 21007371528 is 82517370012.

It is an interprime number because it is at equal distance from previous prime (21007371523) and next prime (21007371533).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21007371492 and 21007371501.

It is not an unprimeable number, because it can be changed into a prime (21007371523) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2456476 + ... + 2465012.

It is an arithmetic number, because the mean of its divisors is an integer number (349631100).

Almost surely, 2^21007371528 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 21007371528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33564585600).

21007371528 is an abundant number, since it is smaller than the sum of its proper divisors (46121799672).

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

21007371528 is a wasteful number, since it uses less digits than its factorization.

21007371528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8812 (or 8805 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 36.

The spelling of 21007371528 in words is "twenty-one billion, seven million, three hundred seventy-one thousand, five hundred twenty-eight".