21161088 has 160 divisors (see below), whose sum is σ = 68251260. Its totient is φ = 6469632.

The previous prime is 21161059. The next prime is 21161089. The reversal of 21161088 is 88016112.

It can be written as a sum of positive squares in 2 ways, for example, as 19289664 + 1871424 = 4392^2 + 1368^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21161089) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 134706 + ... + 134862.

Almost surely, 2^21161088 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21161088, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34125630).

21161088 is an abundant number, since it is smaller than the sum of its proper divisors (47090172).

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

21161088 is a wasteful number, since it uses less digits than its factorization.

21161088 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 196 (or 175 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 21161088 is about 4600.1182593494. The cubic root of 21161088 is about 276.5960652740.

The spelling of 21161088 in words is "twenty-one million, one hundred sixty-one thousand, eighty-eight".