20847431 has 8 divisors (see below), whose sum is σ = 22923264. Its totient is φ = 18801720.

The previous prime is 20847419. The next prime is 20847443. The reversal of 20847431 is 13474802.

It is an interprime number because it is at equal distance from previous prime (20847419) and next prime (20847443).

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

It is a cyclic number.

It is not a de Polignac number, because 20847431 - 2¹⁰ = 20846407 is a prime.

It is a super-2 number, since 2×20847431² = 869230758599522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20847394 and 20847403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20847401) 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, 6065 + ... + 8858.

It is an arithmetic number, because the mean of its divisors is an integer number (2865408).

Almost surely, 2^20847431 is an apocalyptic number.

20847431 is a deficient number, since it is larger than the sum of its proper divisors (2075833).

20847431 is a wasteful number, since it uses less digits than its factorization.

20847431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15061.

The product of its (nonzero) digits is 5376, while the sum is 29.

The square root of 20847431 is about 4565.8987067170. The cubic root of 20847431 is about 275.2226560397. Note that the first 3 decimals are identical.

The spelling of 20847431 in words is "twenty million, eight hundred forty-seven thousand, four hundred thirty-one".