20769408 has 144 divisors (see below), whose sum is σ = 66134250. Its totient is φ = 6251520.

The previous prime is 20769407. The next prime is 20769409. The reversal of 20769408 is 80496702.

It is an interprime number because it is at equal distance from previous prime (20769407) and next prime (20769409).

It can be written as a sum of positive squares in only one way, i.e., 20142144 + 627264 = 4488^2 + 792^2 .

It is a tau number, because it is divible by the number of its divisors (144).

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

It is not an unprimeable number, because it can be changed into a prime (20769401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 139318 + ... + 139466.

Almost surely, 2^20769408 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 20769408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33067125).

20769408 is an abundant number, since it is smaller than the sum of its proper divisors (45364842).

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

20769408 is a wasteful number, since it uses less digits than its factorization.

20769408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 20769408 is about 4557.3465964309. The cubic root of 20769408 is about 274.8788799955.

Adding to 20769408 its product of nonzero digits (24192), we get a square (20793600 = 4560²).

The spelling of 20769408 in words is "twenty million, seven hundred sixty-nine thousand, four hundred eight".