21961360 has 20 divisors (see below), whose sum is σ = 51060348. Its totient is φ = 8784512.

The previous prime is 21961349. The next prime is 21961367. The reversal of 21961360 is 6316912.

It can be written as a sum of positive squares in 2 ways, for example, as 5607424 + 16353936 = 2368^2 + 4044^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (21961367) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 137179 + ... + 137338.

Almost surely, 2^21961360 is an apocalyptic number.

21961360 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21961360 is an abundant number, since it is smaller than the sum of its proper divisors (29098988).

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

21961360 is a wasteful number, since it uses less digits than its factorization.

21961360 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 274530 (or 274524 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 28.

The square root of 21961360 is about 4686.2949117613. The cubic root of 21961360 is about 280.0397902636.

The spelling of 21961360 in words is "twenty-one million, nine hundred sixty-one thousand, three hundred sixty".