20561434 has 4 divisors (see below), whose sum is σ = 30842154. Its totient is φ = 10280716.

The previous prime is 20561423. The next prime is 20561447. The reversal of 20561434 is 43416502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 356409 = 4495^2 + 597^2 .

It is a junction number, because it is equal to n+sod(n) for n = 20561399 and 20561408.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5140357 + ... + 5140360.

Almost surely, 2^20561434 is an apocalyptic number.

20561434 is a deficient number, since it is larger than the sum of its proper divisors (10280720).

20561434 is a wasteful number, since it uses less digits than its factorization.

20561434 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10280719.

The product of its (nonzero) digits is 2880, while the sum is 25.

The square root of 20561434 is about 4534.4717443160. The cubic root of 20561434 is about 273.9583025684.

Adding to 20561434 its reverse (43416502), we get a palindrome (63977936).

The spelling of 20561434 in words is "twenty million, five hundred sixty-one thousand, four hundred thirty-four".