21769380 has 36 divisors (see below), whose sum is σ = 66034332. Its totient is φ = 5805120.

The previous prime is 21769361. The next prime is 21769393. The reversal of 21769380 is 8396712.

21769380 is a `hidden beast` number, since 217 + 69 + 380 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 15539364 + 6230016 = 3942^2 + 2496^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60291 + ... + 60650.

It is an arithmetic number, because the mean of its divisors is an integer number (1834287).

Almost surely, 2^21769380 is an apocalyptic number.

21769380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21769380 is an abundant number, since it is smaller than the sum of its proper divisors (44264952).

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

21769380 is a wasteful number, since it uses less digits than its factorization.

21769380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120956 (or 120951 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 21769380 is about 4665.7668180054. The cubic root of 21769380 is about 279.2213913162.

The spelling of 21769380 in words is "twenty-one million, seven hundred sixty-nine thousand, three hundred eighty".