21151400 has 48 divisors (see below), whose sum is σ = 52078140. Its totient is φ = 7961600.

The previous prime is 21151343. The next prime is 21151433. The reversal of 21151400 is 415112.

It can be written as a sum of positive squares in 6 ways, for example, as 4813636 + 16337764 = 2194^2 + 4042^2 .

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, 290 + ... + 6510.

Almost surely, 2^21151400 is an apocalyptic number.

21151400 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21151400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26039070).

21151400 is an abundant number, since it is smaller than the sum of its proper divisors (30926740).

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

21151400 is a wasteful number, since it uses less digits than its factorization.

21151400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6254 (or 6245 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 14.

The square root of 21151400 is about 4599.0651223917. The cubic root of 21151400 is about 276.5538482935.

Adding to 21151400 its reverse (415112), we get a palindrome (21566512).

The spelling of 21151400 in words is "twenty-one million, one hundred fifty-one thousand, four hundred".