20645442 has 40 divisors (see below), whose sum is σ = 47764992. Its totient is φ = 6658200.

The previous prime is 20645441. The next prime is 20645453. The reversal of 20645442 is 24454602.

20645442 is a `hidden beast` number, since 206 + 454 + 4 + 2 = 666.

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 (20645441) 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, 2967 + ... + 7077.

Almost surely, 2^20645442 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20645442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23882496).

20645442 is an abundant number, since it is smaller than the sum of its proper divisors (27119550).

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

20645442 is a wasteful number, since it uses less digits than its factorization.

20645442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4156 (or 4147 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 27.

The square root of 20645442 is about 4543.7255638958. The cubic root of 20645442 is about 274.3309000613.

The spelling of 20645442 in words is "twenty million, six hundred forty-five thousand, four hundred forty-two".