20478729 has 8 divisors (see below), whose sum is σ = 27402592. Its totient is φ = 13603680.

The previous prime is 20478719. The next prime is 20478739. The reversal of 20478729 is 92787402.

It is an interprime number because it is at equal distance from previous prime (20478719) and next prime (20478739).

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

It is not a de Polignac number, because 20478729 - 2¹² = 20474633 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20478719) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11212 + ... + 12909.

It is an arithmetic number, because the mean of its divisors is an integer number (3425324).

Almost surely, 2^20478729 is an apocalyptic number.

It is an amenable number.

20478729 is a deficient number, since it is larger than the sum of its proper divisors (6923863).

20478729 is a wasteful number, since it uses less digits than its factorization.

20478729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24407.

The product of its (nonzero) digits is 56448, while the sum is 39.

The square root of 20478729 is about 4525.3429704278. The cubic root of 20478729 is about 273.5904915089.

The spelling of 20478729 in words is "twenty million, four hundred seventy-eight thousand, seven hundred twenty-nine".