20805542 has 4 divisors (see below), whose sum is σ = 31208316. Its totient is φ = 10402770.

The previous prime is 20805539. The next prime is 20805553. The reversal of 20805542 is 24550802.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 24550802 = 2 ⋅12275401.

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, 5201384 + ... + 5201387.

It is an arithmetic number, because the mean of its divisors is an integer number (7802079).

Almost surely, 2^20805542 is an apocalyptic number.

20805542 is a deficient number, since it is larger than the sum of its proper divisors (10402774).

20805542 is a wasteful number, since it uses less digits than its factorization.

20805542 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10402773.

The product of its (nonzero) digits is 3200, while the sum is 26.

The square root of 20805542 is about 4561.3092418734. The cubic root of 20805542 is about 275.0381963473.

The spelling of 20805542 in words is "twenty million, eight hundred five thousand, five hundred forty-two".