21007116 has 36 divisors (see below), whose sum is σ = 57187312. Its totient is φ = 6463584.

The previous prime is 21007111. The next prime is 21007123. The reversal of 21007116 is 61170012.

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

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (21007111) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21976 + ... + 22911.

Almost surely, 2^21007116 is an apocalyptic number.

21007116 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21007116 is an abundant number, since it is smaller than the sum of its proper divisors (36180196).

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

21007116 is a wasteful number, since it uses less digits than its factorization.

21007116 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44910 (or 44905 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 18.

The square root of 21007116 is about 4583.3520484466. The cubic root of 21007116 is about 275.9235768243.

Adding to 21007116 its reverse (61170012), we get a palindrome (82177128).

It can be divided in two parts, 2100 and 7116, that added together give a square (9216 = 96²).

The spelling of 21007116 in words is "twenty-one million, seven thousand, one hundred sixteen".