20248561 has 4 divisors (see below), whose sum is σ = 20533824. Its totient is φ = 19963300.

The previous prime is 20248559. The next prime is 20248567. The reversal of 20248561 is 16584202.

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, and also an emirpimes, since its reverse is a distinct semiprime: 16584202 = 2 ⋅8292101.

It is a cyclic number.

It is not a de Polignac number, because 20248561 - 2¹ = 20248559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20248567) 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, 142525 + ... + 142666.

It is an arithmetic number, because the mean of its divisors is an integer number (5133456).

Almost surely, 2^20248561 is an apocalyptic number.

It is an amenable number.

20248561 is a deficient number, since it is larger than the sum of its proper divisors (285263).

20248561 is an equidigital number, since it uses as much as digits as its factorization.

20248561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285262.

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

The square root of 20248561 is about 4499.8401082705. The cubic root of 20248561 is about 272.5616323854.

It can be divided in two parts, 2024 and 8561, that added together give a triangular number (10585 = T₁₄₅).

The spelling of 20248561 in words is "twenty million, two hundred forty-eight thousand, five hundred sixty-one".