20865742 has 4 divisors (see below), whose sum is σ = 31298616. Its totient is φ = 10432870.

The previous prime is 20865739. The next prime is 20865751. The reversal of 20865742 is 24756802.

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

It is a junction number, because it is equal to n+sod(n) for n = 20865698 and 20865707.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5216434 + ... + 5216437.

It is an arithmetic number, because the mean of its divisors is an integer number (7824654).

Almost surely, 2^20865742 is an apocalyptic number.

20865742 is a deficient number, since it is larger than the sum of its proper divisors (10432874).

20865742 is a wasteful number, since it uses less digits than its factorization.

20865742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10432873.

The product of its (nonzero) digits is 26880, while the sum is 34.

The square root of 20865742 is about 4567.9034578240. The cubic root of 20865742 is about 275.3032115654.

It can be divided in two parts, 20865 and 742, that multiplied together give a triangular number (15481830 = T₅₅₆₄).

The spelling of 20865742 in words is "twenty million, eight hundred sixty-five thousand, seven hundred forty-two".