20742671 has 4 divisors (see below), whose sum is σ = 20901144. Its totient is φ = 20584200.

The previous prime is 20742653. The next prime is 20742677. The reversal of 20742671 is 17624702.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20742671 - 2¹⁸ = 20480527 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20742677) 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 3 ways as a sum of consecutive naturals, for example, 79040 + ... + 79301.

It is an arithmetic number, because the mean of its divisors is an integer number (5225286).

Almost surely, 2^20742671 is an apocalyptic number.

20742671 is a deficient number, since it is larger than the sum of its proper divisors (158473).

20742671 is a wasteful number, since it uses less digits than its factorization.

20742671 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158472.

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 20742671 is about 4554.4122562632. The cubic root of 20742671 is about 274.7608764302.

The spelling of 20742671 in words is "twenty million, seven hundred forty-two thousand, six hundred seventy-one".