21211010400 has 72 divisors (see below), whose sum is σ = 69041846664. Its totient is φ = 5656268800.

The previous prime is 21211010399. The next prime is 21211010407. The reversal of 21211010400 is 401011212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211010407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4416561 + ... + 4421360.

It is an arithmetic number, because the mean of its divisors is an integer number (958914537).

Almost surely, 2^21211010400 is an apocalyptic number.

21211010400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21211010400 is an abundant number, since it is smaller than the sum of its proper divisors (47830836264).

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

21211010400 is a wasteful number, since it uses less digits than its factorization.

21211010400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8837944 (or 8837931 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21211010400 its reverse (401011212), we get a palindrome (21612021612).

The spelling of 21211010400 in words is "twenty-one billion, two hundred eleven million, ten thousand, four hundred".