21607380 has 36 divisors (see below), whose sum is σ = 65542932. Its totient is φ = 5761920.

The previous prime is 21607367. The next prime is 21607381. The reversal of 21607380 is 8370612.

21607380 is a `hidden beast` number, since 21 + 607 + 38 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3048516 + 18558864 = 1746^2 + 4308^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21607381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 59841 + ... + 60200.

It is an arithmetic number, because the mean of its divisors is an integer number (1820637).

Almost surely, 2^21607380 is an apocalyptic number.

21607380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21607380 is an abundant number, since it is smaller than the sum of its proper divisors (43935552).

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

21607380 is a wasteful number, since it uses less digits than its factorization.

21607380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120056 (or 120051 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21607380 is about 4648.3739092289. The cubic root of 21607380 is about 278.5270439289.

Adding to 21607380 its reverse (8370612), we get a palindrome (29977992).

It can be divided in two parts, 216073 and 80, that added together give a triangular number (216153 = T₆₅₇).

The spelling of 21607380 in words is "twenty-one million, six hundred seven thousand, three hundred eighty".