20742140 has 24 divisors (see below), whose sum is σ = 43985760. Its totient is φ = 8215488.

The previous prime is 20742109. The next prime is 20742151. The reversal of 20742140 is 4124702.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2975 + ... + 7094.

It is an arithmetic number, because the mean of its divisors is an integer number (1832740).

Almost surely, 2^20742140 is an apocalyptic number.

20742140 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20742140 is an abundant number, since it is smaller than the sum of its proper divisors (23243620).

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

20742140 is a wasteful number, since it uses less digits than its factorization.

20742140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10181 (or 10179 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 20.

The square root of 20742140 is about 4554.3539607720. The cubic root of 20742140 is about 274.7585318387.

Adding to 20742140 its reverse (4124702), we get a palindrome (24866842).

The spelling of 20742140 in words is "twenty million, seven hundred forty-two thousand, one hundred forty".