21400202550 has 48 divisors (see below), whose sum is σ = 55865799360. Its totient is φ = 5406366240.

The previous prime is 21400202543. The next prime is 21400202557. The reversal of 21400202550 is 5520200412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21400202543) and next prime (21400202557).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400202557) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3751572 + ... + 3757271.

It is an arithmetic number, because the mean of its divisors is an integer number (1163870820).

Almost surely, 2^21400202550 is an apocalyptic number.

21400202550 is an abundant number, since it is smaller than the sum of its proper divisors (34465596810).

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

21400202550 is a wasteful number, since it uses less digits than its factorization.

21400202550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7508877 (or 7508872 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 21.

Adding to 21400202550 its reverse (5520200412), we get a palindrome (26920402962).

The spelling of 21400202550 in words is "twenty-one billion, four hundred million, two hundred two thousand, five hundred fifty".