20878461 has 6 divisors (see below), whose sum is σ = 30157790. Its totient is φ = 13918968.

The previous prime is 20878453. The next prime is 20878477. The reversal of 20878461 is 16487802.

It can be written as a sum of positive squares in only one way, i.e., 15444900 + 5433561 = 3930^2 + 2331^2 .

It is not a de Polignac number, because 20878461 - 2³ = 20878453 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 (20878441) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1159906 + ... + 1159923.

Almost surely, 2^20878461 is an apocalyptic number.

It is an amenable number.

20878461 is a deficient number, since it is larger than the sum of its proper divisors (9279329).

20878461 is a wasteful number, since it uses less digits than its factorization.

20878461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2319835 (or 2319832 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 20878461 is about 4569.2954599150. The cubic root of 20878461 is about 275.3591384895.

The spelling of 20878461 in words is "twenty million, eight hundred seventy-eight thousand, four hundred sixty-one".