1866089521901 has 4 divisors (see below), whose sum is σ = 2035734023904. Its totient is φ = 1696445019900.

The previous prime is 1866089521871. The next prime is 1866089521999. The reversal of 1866089521901 is 1091259806681.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1866089521901 - 2¹⁸ = 1866089259757 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866089521801) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 84822250985 + ... + 84822251006.

It is an arithmetic number, because the mean of its divisors is an integer number (508933505976).

Almost surely, 2^{1866089521901} is an apocalyptic number.

1866089521901 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1866089521901 is a deficient number, since it is larger than the sum of its proper divisors (169644502003).

1866089521901 is a wasteful number, since it uses less digits than its factorization.

1866089521901 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169644502002.

The product of its (nonzero) digits is 1866240, while the sum is 56.

The spelling of 1866089521901 in words is "one trillion, eight hundred sixty-six billion, eighty-nine million, five hundred twenty-one thousand, nine hundred one".