20840742 has 96 divisors (see below), whose sum is σ = 53464320. Its totient is φ = 5840640.

The previous prime is 20840717. The next prime is 20840761. The reversal of 20840742 is 24704802.

It is a super-2 number, since 2×20840742² = 868673054221128, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 672267 + ... + 672297.

It is an arithmetic number, because the mean of its divisors is an integer number (556920).

Almost surely, 2^20840742 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20840742, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26732160).

20840742 is an abundant number, since it is smaller than the sum of its proper divisors (32623578).

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

20840742 is a wasteful number, since it uses less digits than its factorization.

20840742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 27.

The square root of 20840742 is about 4565.1661525075. The cubic root of 20840742 is about 275.1932173800.

The spelling of 20840742 in words is "twenty million, eight hundred forty thousand, seven hundred forty-two".