20861405 has 8 divisors (see below), whose sum is σ = 25200384. Its totient is φ = 16578000.

The previous prime is 20861389. The next prime is 20861413. The reversal of 20861405 is 50416802.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20861405 - 2⁴ = 20861389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13061 + ... + 14570.

It is an arithmetic number, because the mean of its divisors is an integer number (3150048).

Almost surely, 2^20861405 is an apocalyptic number.

It is an amenable number.

20861405 is a deficient number, since it is larger than the sum of its proper divisors (4338979).

20861405 is a wasteful number, since it uses less digits than its factorization.

20861405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27787.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 20861405 is about 4567.4287077085. The cubic root of 20861405 is about 275.2841360753.

The spelling of 20861405 in words is "twenty million, eight hundred sixty-one thousand, four hundred five".