21345400 has 24 divisors (see below), whose sum is σ = 49628520. Its totient is φ = 8538080.

The previous prime is 21345397. The next prime is 21345409. The reversal of 21345400 is 454312.

It is a super-2 number, since 2×21345400² = 911252202320000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21345409) 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, 53164 + ... + 53563.

It is an arithmetic number, because the mean of its divisors is an integer number (2067855).

Almost surely, 2^21345400 is an apocalyptic number.

21345400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21345400 is an abundant number, since it is smaller than the sum of its proper divisors (28283120).

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

21345400 is a wasteful number, since it uses less digits than its factorization.

21345400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106743 (or 106734 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21345400 is about 4620.1082238406. The cubic root of 21345400 is about 277.3967908804.

Adding to 21345400 its reverse (454312), we get a palindrome (21799712).

The spelling of 21345400 in words is "twenty-one million, three hundred forty-five thousand, four hundred".