21101004 has 18 divisors (see below), whose sum is σ = 53338740. Its totient is φ = 7033656.

The previous prime is 21100999. The next prime is 21101027. The reversal of 21101004 is 40010112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (18).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

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, 293034 + ... + 293105.

Almost surely, 2^21101004 is an apocalyptic number.

It is an amenable number.

21101004 is an abundant number, since it is smaller than the sum of its proper divisors (32237736).

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

21101004 is a wasteful number, since it uses less digits than its factorization.

21101004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 586149 (or 586144 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 21101004 is about 4593.5829153287. The cubic root of 21101004 is about 276.3340316148.

Adding to 21101004 its reverse (40010112), we get a palindrome (61111116).

It can be divided in two parts, 21 and 101004, that added together give a triangular number (101025 = T₄₄₉).

The spelling of 21101004 in words is "twenty-one million, one hundred one thousand, four".