21616740 has 48 divisors (see below), whose sum is σ = 67253760. Its totient is φ = 5764320.

The previous prime is 21616729. The next prime is 21616747. The reversal of 21616740 is 4761612.

21616740 is a `hidden beast` number, since 2 + 1 + 616 + 7 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21616747) 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 15 ways as a sum of consecutive naturals, for example, 19476 + ... + 20555.

It is an arithmetic number, because the mean of its divisors is an integer number (1401120).

Almost surely, 2^21616740 is an apocalyptic number.

21616740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21616740 is an abundant number, since it is smaller than the sum of its proper divisors (45637020).

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

21616740 is a wasteful number, since it uses less digits than its factorization.

21616740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40049 (or 40041 counting only the distinct ones).

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

The square root of 21616740 is about 4649.3806039084. The cubic root of 21616740 is about 278.5672560660.

The spelling of 21616740 in words is "twenty-one million, six hundred sixteen thousand, seven hundred forty".