1861891406011 has 32 divisors (see below), whose sum is σ = 2451370400640. Its totient is φ = 1372195454976.

The previous prime is 1861891406009. The next prime is 1861891406017. The reversal of 1861891406011 is 1106041981681.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1861891406011 - 2¹ = 1861891406009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1861891406017) 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, 6053806 + ... + 6353923.

It is an arithmetic number, because the mean of its divisors is an integer number (76605325020).

Almost surely, 2^{1861891406011} is an apocalyptic number.

1861891406011 is a deficient number, since it is larger than the sum of its proper divisors (589478994629).

1861891406011 is a wasteful number, since it uses less digits than its factorization.

1861891406011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12407863.

The product of its (nonzero) digits is 82944, while the sum is 46.

The spelling of 1861891406011 in words is "one trillion, eight hundred sixty-one billion, eight hundred ninety-one million, four hundred six thousand, eleven".