20545757 has 4 divisors (see below), whose sum is σ = 20560320. Its totient is φ = 20531196.

The previous prime is 20545711. The next prime is 20545769. The reversal of 20545757 is 75754502.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20545757 - 2¹⁴ = 20529373 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 (20545957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4907 + ... + 8072.

It is an arithmetic number, because the mean of its divisors is an integer number (5140080).

Almost surely, 2^20545757 is an apocalyptic number.

It is an amenable number.

20545757 is a deficient number, since it is larger than the sum of its proper divisors (14563).

20545757 is a wasteful number, since it uses less digits than its factorization.

20545757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14562.

The product of its (nonzero) digits is 49000, while the sum is 35.

The square root of 20545757 is about 4532.7427679055. The cubic root of 20545757 is about 273.8886586532. Note that the first 3 decimals are identical.

The spelling of 20545757 in words is "twenty million, five hundred forty-five thousand, seven hundred fifty-seven".