11981358021 has 16 divisors (see below), whose sum is σ = 16124232960. Its totient is φ = 7913095680.

The previous prime is 11981357981. The next prime is 11981358031. The reversal of 11981358021 is 12085318911.

It is not a de Polignac number, because 11981358021 - 2¹³ = 11981349829 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11981358031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 820260 + ... + 834738.

It is an arithmetic number, because the mean of its divisors is an integer number (1007764560).

Almost surely, 2^11981358021 is an apocalyptic number.

It is an amenable number.

11981358021 is a deficient number, since it is larger than the sum of its proper divisors (4142874939).

11981358021 is a wasteful number, since it uses less digits than its factorization.

11981358021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17036.

The product of its (nonzero) digits is 17280, while the sum is 39.

The spelling of 11981358021 in words is "eleven billion, nine hundred eighty-one million, three hundred fifty-eight thousand, twenty-one".