21005088 has 48 divisors (see below), whose sum is σ = 59383296. Its totient is φ = 6462720.

The previous prime is 21005087. The next prime is 21005111. The reversal of 21005088 is 88050012.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is not an unprimeable number, because it can be changed into a prime (21005087) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7168 + ... + 9663.

It is an arithmetic number, because the mean of its divisors is an integer number (1237152).

Almost surely, 2^21005088 is an apocalyptic number.

It is an amenable number.

21005088 is an abundant number, since it is smaller than the sum of its proper divisors (38378208).

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

21005088 is a wasteful number, since it uses less digits than its factorization.

21005088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16857 (or 16849 counting only the distinct ones).

The product of its (nonzero) digits is 640, while the sum is 24.

The square root of 21005088 is about 4583.1308076467. The cubic root of 21005088 is about 275.9146974360.

The spelling of 21005088 in words is "twenty-one million, five thousand, eighty-eight".