21012251252450 has 24 divisors (see below), whose sum is σ = 39083036775552. Its totient is φ = 8404846856720.

The previous prime is 21012251252393. The next prime is 21012251252561. The reversal of 21012251252450 is 5425215221012.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7096787 + ... + 9611913.

It is an arithmetic number, because the mean of its divisors is an integer number (1628459865648).

Almost surely, 2^{21012251252450} is an apocalyptic number.

21012251252450 is a deficient number, since it is larger than the sum of its proper divisors (18070785523102).

21012251252450 is a wasteful number, since it uses less digits than its factorization.

21012251252450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2682226 (or 2682221 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 32.

Adding to 21012251252450 its reverse (5425215221012), we get a palindrome (26437466473462).

The spelling of 21012251252450 in words is "twenty-one trillion, twelve billion, two hundred fifty-one million, two hundred fifty-two thousand, four hundred fifty".