21109977 has 40 divisors (see below), whose sum is σ = 37233152.
Its totient is φ = 11664000.
The previous prime is 21109973. The next prime is 21109987. The reversal of 21109977 is 77990112.
It is not a de Polignac number, because 21109977 - 22 = 21109973 is a prime.
It is a super-2 number, since 2×211099772 = 891262257881058, which contains 22 as substring.
It is a Duffinian number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (21109973) 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 39 ways as a sum of consecutive naturals, for example, 16977 + ... + 18177.
Almost surely, 221109977 is an apocalyptic number.
21109977 is a gapful number since it is divisible by the number (27) formed by its first and last digit.
It is an amenable number.
21109977 is a deficient number, since it is larger than the sum of its proper divisors (16123175).
21109977 is a wasteful number, since it uses less digits than its factorization.
21109977 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1251 (or 1242 counting only the distinct ones).
The product of its (nonzero) digits is 7938, while the sum is 36.
The square root of 21109977 is about 4594.5595001044.
The cubic root of 21109977 is about 276.3731955314.
The spelling of 21109977 in words is "twenty-one million, one hundred nine thousand, nine hundred seventy-seven".