20781949523 has 8 divisors (see below), whose sum is σ = 23162544720. Its totient is φ = 18530035200.

The previous prime is 20781949519. The next prime is 20781949553. The reversal of 20781949523 is 32594918702.

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 20781949523 - 2² = 20781949519 is a prime.

It is a super-3 number, since 3×20781949523³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20781949553) 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, 32169878 + ... + 32170523.

It is an arithmetic number, because the mean of its divisors is an integer number (2895318090).

Almost surely, 2^20781949523 is an apocalyptic number.

20781949523 is a deficient number, since it is larger than the sum of its proper divisors (2380595197).

20781949523 is a wasteful number, since it uses less digits than its factorization.

20781949523 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64340437.

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 20781949523 in words is "twenty billion, seven hundred eighty-one million, nine hundred forty-nine thousand, five hundred twenty-three".