20781732347 has 2 divisors, whose sum is σ = 20781732348. Its totient is φ = 20781732346.

The previous prime is 20781732341. The next prime is 20781732371. The reversal of 20781732347 is 74323718702.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20781732347 - 2²² = 20777538043 is a prime.

It is a super-2 number, since 2×20781732347² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20781732298 and 20781732307.

It is not a weakly prime, because it can be changed into another prime (20781732341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10390866173 + 10390866174.

It is an arithmetic number, because the mean of its divisors is an integer number (10390866174).

Almost surely, 2^20781732347 is an apocalyptic number.

20781732347 is a deficient number, since it is larger than the sum of its proper divisors (1).

20781732347 is an equidigital number, since it uses as much as digits as its factorization.

20781732347 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 395136, while the sum is 44.

The spelling of 20781732347 in words is "twenty billion, seven hundred eighty-one million, seven hundred thirty-two thousand, three hundred forty-seven".