20556461 has 4 divisors (see below), whose sum is σ = 21638400. Its totient is φ = 19474524.

The previous prime is 20556433. The next prime is 20556467. The reversal of 20556461 is 16465502.

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 20556461 - 2⁶ = 20556397 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20556467) 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, 540941 + ... + 540978.

It is an arithmetic number, because the mean of its divisors is an integer number (5409600).

Almost surely, 2^20556461 is an apocalyptic number.

It is an amenable number.

20556461 is a deficient number, since it is larger than the sum of its proper divisors (1081939).

20556461 is a wasteful number, since it uses less digits than its factorization.

20556461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1081938.

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 20556461 is about 4533.9233562115. The cubic root of 20556461 is about 273.9362142178.

The spelling of 20556461 in words is "twenty million, five hundred fifty-six thousand, four hundred sixty-one".