1861621822221 has 32 divisors (see below), whose sum is σ = 3134217535488. Its totient is φ = 957677571840.

The previous prime is 1861621822217. The next prime is 1861621822297. The reversal of 1861621822221 is 1222281261681.

It is not a de Polignac number, because 1861621822221 - 2² = 1861621822217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861621820221) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 113353245 + ... + 113369666.

It is an arithmetic number, because the mean of its divisors is an integer number (97944297984).

Almost surely, 2^{1861621822221} is an apocalyptic number.

It is an amenable number.

1861621822221 is a deficient number, since it is larger than the sum of its proper divisors (1272595713267).

1861621822221 is a wasteful number, since it uses less digits than its factorization.

1861621822221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 226722961.

The product of its digits is 73728, while the sum is 42.

The spelling of 1861621822221 in words is "one trillion, eight hundred sixty-one billion, six hundred twenty-one million, eight hundred twenty-two thousand, two hundred twenty-one".