20561416 has 8 divisors (see below), whose sum is σ = 38552670. Its totient is φ = 10280704.

The previous prime is 20561413. The next prime is 20561417. The reversal of 20561416 is 61416502.

It can be written as a sum of positive squares in only one way, i.e., 18096516 + 2464900 = 4254^2 + 1570^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (20561413) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1285081 + ... + 1285096.

Almost surely, 2^20561416 is an apocalyptic number.

It is an amenable number.

20561416 is a deficient number, since it is larger than the sum of its proper divisors (17991254).

20561416 is a wasteful number, since it uses less digits than its factorization.

20561416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2570183 (or 2570179 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 20561416 is about 4534.4697595198. The cubic root of 20561416 is about 273.9582226251.

Adding to 20561416 its reverse (61416502), we get a palindrome (81977918).

The spelling of 20561416 in words is "twenty million, five hundred sixty-one thousand, four hundred sixteen".