21677216 has 24 divisors (see below), whose sum is σ = 46557504. Its totient is φ = 9853120.

The previous prime is 21677213. The next prime is 21677221. The reversal of 21677216 is 61277612.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21677213) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30440 + ... + 31143.

It is an arithmetic number, because the mean of its divisors is an integer number (1939896).

Almost surely, 2^21677216 is an apocalyptic number.

It is an amenable number.

21677216 is an abundant number, since it is smaller than the sum of its proper divisors (24880288).

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

21677216 is a wasteful number, since it uses less digits than its factorization.

21677216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61604 (or 61596 counting only the distinct ones).

The product of its digits is 7056, while the sum is 32.

The square root of 21677216 is about 4655.8797235324. The cubic root of 21677216 is about 278.8267917690.

The spelling of 21677216 in words is "twenty-one million, six hundred seventy-seven thousand, two hundred sixteen".