1218644201990 has 64 divisors (see below), whose sum is σ = 2307607626240. Its totient is φ = 462719262720.

The previous prime is 1218644201963. The next prime is 1218644202001. The reversal of 1218644201990 is 991024468121.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 101810726 + ... + 101822694.

It is an arithmetic number, because the mean of its divisors is an integer number (36056369160).

Almost surely, 2^{1218644201990} is an apocalyptic number.

1218644201990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1218644201990 is a deficient number, since it is larger than the sum of its proper divisors (1088963424250).

1218644201990 is a wasteful number, since it uses less digits than its factorization.

1218644201990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18257.

The product of its (nonzero) digits is 248832, while the sum is 47.

The spelling of 1218644201990 in words is "one trillion, two hundred eighteen billion, six hundred forty-four million, two hundred one thousand, nine hundred ninety".