20781212540 has 48 divisors (see below), whose sum is σ = 49677788160. Its totient is φ = 7228246080.

The previous prime is 20781212521. The next prime is 20781212567. The reversal of 20781212540 is 4521218702.

It is a junction number, because it is equal to n+sod(n) for n = 20781212497 and 20781212506.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2048420 + ... + 2058539.

It is an arithmetic number, because the mean of its divisors is an integer number (1034953920).

Almost surely, 2^20781212540 is an apocalyptic number.

20781212540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20781212540 is an abundant number, since it is smaller than the sum of its proper divisors (28896575620).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20781212540 is a wasteful number, since it uses less digits than its factorization.

20781212540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4107002 (or 4107000 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 32.

The spelling of 20781212540 in words is "twenty billion, seven hundred eighty-one million, two hundred twelve thousand, five hundred forty".