20542681 has 8 divisors (see below), whose sum is σ = 22282344. Its totient is φ = 18862080.

The previous prime is 20542673. The next prime is 20542729. The reversal of 20542681 is 18624502.

It can be written as a sum of positive squares in 4 ways, for example, as 292681 + 20250000 = 541^2 + 4500^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20542681 - 2³ = 20542673 is a prime.

It is a super-2 number, since 2×20542681² = 844003485335522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20542651) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14040 + ... + 15433.

It is an arithmetic number, because the mean of its divisors is an integer number (2785293).

Almost surely, 2^20542681 is an apocalyptic number.

It is an amenable number.

20542681 is a deficient number, since it is larger than the sum of its proper divisors (1739663).

20542681 is a wasteful number, since it uses less digits than its factorization.

20542681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29531.

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 20542681 is about 4532.4034462965. The cubic root of 20542681 is about 273.8749895931.

The spelling of 20542681 in words is "twenty million, five hundred forty-two thousand, six hundred eighty-one".