21101433391 has 4 divisors (see below), whose sum is σ = 21103342632. Its totient is φ = 21099524152.

The previous prime is 21101433341. The next prime is 21101433401. The reversal of 21101433391 is 19333410112.

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

It is a cyclic number.

It is not a de Polignac number, because 21101433391 - 2⁷ = 21101433263 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 (21101433341) 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, 937945 + ... + 960178.

It is an arithmetic number, because the mean of its divisors is an integer number (5275835658).

Almost surely, 2^21101433391 is an apocalyptic number.

21101433391 is a deficient number, since it is larger than the sum of its proper divisors (1909241).

21101433391 is a wasteful number, since it uses less digits than its factorization.

21101433391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1909240.

The product of its (nonzero) digits is 1944, while the sum is 28.

The spelling of 21101433391 in words is "twenty-one billion, one hundred one million, four hundred thirty-three thousand, three hundred ninety-one".