14215021991 has 4 divisors (see below), whose sum is σ = 14215297152. Its totient is φ = 14214746832.

The previous prime is 14215021981. The next prime is 14215021993. The reversal of 14215021991 is 19912051241.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-14215021991 is a prime.

It is a super-2 number, since 2×14215021991² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (14215021993) 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, 34190 + ... + 172043.

It is an arithmetic number, because the mean of its divisors is an integer number (3553824288).

Almost surely, 2^14215021991 is an apocalyptic number.

14215021991 is a deficient number, since it is larger than the sum of its proper divisors (275161).

14215021991 is an equidigital number, since it uses as much as digits as its factorization.

14215021991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275160.

The product of its (nonzero) digits is 6480, while the sum is 35.

The spelling of 14215021991 in words is "fourteen billion, two hundred fifteen million, twenty-one thousand, nine hundred ninety-one".