21500001400 has 24 divisors (see below), whose sum is σ = 49987503720. Its totient is φ = 8600000480.

The previous prime is 21500001373. The next prime is 21500001407. The reversal of 21500001400 is 410000512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500001407) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 53749804 + ... + 53750203.

It is an arithmetic number, because the mean of its divisors is an integer number (2082812655).

Almost surely, 2^21500001400 is an apocalyptic number.

21500001400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21500001400 is an abundant number, since it is smaller than the sum of its proper divisors (28487502320).

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

21500001400 is a wasteful number, since it uses less digits than its factorization.

21500001400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107500023 (or 107500014 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

Adding to 21500001400 its reverse (410000512), we get a palindrome (21910001912).

The spelling of 21500001400 in words is "twenty-one billion, five hundred million, one thousand, four hundred".