21100977 has 6 divisors (see below), whose sum is σ = 30479202. Its totient is φ = 14067312.

The previous prime is 21100969. The next prime is 21100993. The reversal of 21100977 is 77900112.

It can be written as a sum of positive squares in only one way, i.e., 20711601 + 389376 = 4551^2 + 624^2 .

It is not a de Polignac number, because 21100977 - 2³ = 21100969 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21100977.

It is not an unprimeable number, because it can be changed into a prime (21100967) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1172268 + ... + 1172285.

It is an arithmetic number, because the mean of its divisors is an integer number (5079867).

Almost surely, 2^21100977 is an apocalyptic number.

It is an amenable number.

21100977 is a deficient number, since it is larger than the sum of its proper divisors (9378225).

21100977 is a wasteful number, since it uses less digits than its factorization.

21100977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2344559 (or 2344556 counting only the distinct ones).

The product of its (nonzero) digits is 882, while the sum is 27.

The square root of 21100977 is about 4593.5799764454. The cubic root of 21100977 is about 276.3339137528. Note that the first 3 decimals are identical.

The spelling of 21100977 in words is "twenty-one million, one hundred thousand, nine hundred seventy-seven".