121867786817838 has 40 divisors (see below), whose sum is σ = 273079730575080. Its totient is φ = 40621760217360.

The previous prime is 121867786817801. The next prime is 121867786817869. The reversal of 121867786817838 is 838718687768121.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 191833 + ... + 15613211.

It is an arithmetic number, because the mean of its divisors is an integer number (6826993264377).

Almost surely, 2^{121867786817838} is an apocalyptic number.

121867786817838 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

121867786817838 is an abundant number, since it is smaller than the sum of its proper divisors (151211943757242).

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

121867786817838 is a wasteful number, since it uses less digits than its factorization.

121867786817838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15470174 (or 15470165 counting only the distinct ones).

The product of its digits is 2427715584, while the sum is 81.

The spelling of 121867786817838 in words is "one hundred twenty-one trillion, eight hundred sixty-seven billion, seven hundred eighty-six million, eight hundred seventeen thousand, eight hundred thirty-eight".