20501811819731 has 18 divisors (see below), whose sum is σ = 23380703787252. Its totient is φ = 17827362105520.

The previous prime is 20501811819721. The next prime is 20501811819737. The reversal of 20501811819731 is 13791811810502.

It is a happy number.

It is not a de Polignac number, because 20501811819731 - 2²² = 20501807625427 is a prime.

It is a super-2 number, since 2×20501811819731² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20501811819737) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 345368705 + ... + 345428061.

Almost surely, 2^{20501811819731} is an apocalyptic number.

20501811819731 is a deficient number, since it is larger than the sum of its proper divisors (2878891967521).

20501811819731 is an frugal number, since it uses more digits than its factorization.

20501811819731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118771 (or 59391 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 47.

The spelling of 20501811819731 in words is "twenty trillion, five hundred one billion, eight hundred eleven million, eight hundred nineteen thousand, seven hundred thirty-one".