21161300 has 36 divisors (see below), whose sum is σ = 47509980. Its totient is φ = 8171520.

The previous prime is 21161297. The next prime is 21161317. The reversal of 21161300 is 316112.

21161300 = 908² + 909² + ... + 932².

It can be written as a sum of positive squares in 6 ways, for example, as 929296 + 20232004 = 964^2 + 4498^2 .

It is a super-3 number, since 3×21161300³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 749 + ... + 6548.

Almost surely, 2^21161300 is an apocalyptic number.

21161300 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21161300 is an abundant number, since it is smaller than the sum of its proper divisors (26348680).

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

21161300 is a wasteful number, since it uses less digits than its factorization.

21161300 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7340 (or 7333 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 21161300 is about 4600.1413021776. The cubic root of 21161300 is about 276.5969889532.

Adding to 21161300 its reverse (316112), we get a palindrome (21477412).

The spelling of 21161300 in words is "twenty-one million, one hundred sixty-one thousand, three hundred".