21161244401 has 4 divisors (see below), whose sum is σ = 23084993904. Its totient is φ = 19237494900.

The previous prime is 21161244389. The next prime is 21161244431. The reversal of 21161244401 is 10444216112.

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 21161244401 - 2¹⁸ = 21160982257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21161244431) 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, 961874735 + ... + 961874756.

It is an arithmetic number, because the mean of its divisors is an integer number (5771248476).

Almost surely, 2^21161244401 is an apocalyptic number.

It is an amenable number.

21161244401 is a deficient number, since it is larger than the sum of its proper divisors (1923749503).

21161244401 is a wasteful number, since it uses less digits than its factorization.

21161244401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1923749502.

The product of its (nonzero) digits is 1536, while the sum is 26.

It can be divided in two parts, 21161 and 244401, that added together give a palindrome (265562).

The spelling of 21161244401 in words is "twenty-one billion, one hundred sixty-one million, two hundred forty-four thousand, four hundred one".