21002451450 has 48 divisors (see below), whose sum is σ = 52435706400. Its totient is φ = 5563059520.

The previous prime is 21002451409. The next prime is 21002451523. The reversal of 21002451450 is 5415420012.

It is a super-2 number, since 2×21002451450² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21002451450.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 447504 + ... + 492203.

It is an arithmetic number, because the mean of its divisors is an integer number (1092410550).

Almost surely, 2^21002451450 is an apocalyptic number.

21002451450 is an abundant number, since it is smaller than the sum of its proper divisors (31433254950).

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

21002451450 is a wasteful number, since it uses less digits than its factorization.

21002451450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 939871 (or 939866 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 24.

Adding to 21002451450 its reverse (5415420012), we get a palindrome (26417871462).

The spelling of 21002451450 in words is "twenty-one billion, two million, four hundred fifty-one thousand, four hundred fifty".