11981421305 has 16 divisors (see below), whose sum is σ = 16494153984. Its totient is φ = 8184586560.

The previous prime is 11981421271. The next prime is 11981421367. The reversal of 11981421305 is 50312418911.

It is a happy number.

It is not a de Polignac number, because 11981421305 - 2¹⁶ = 11981355769 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 641606 + ... + 660015.

It is an arithmetic number, because the mean of its divisors is an integer number (1030884624).

Almost surely, 2^11981421305 is an apocalyptic number.

It is an amenable number.

11981421305 is a deficient number, since it is larger than the sum of its proper divisors (4512732679).

11981421305 is a wasteful number, since it uses less digits than its factorization.

11981421305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1301896.

The product of its (nonzero) digits is 8640, while the sum is 35.

The spelling of 11981421305 in words is "eleven billion, nine hundred eighty-one million, four hundred twenty-one thousand, three hundred five".