21403155353 has 4 divisors (see below), whose sum is σ = 21526873188. Its totient is φ = 21279437520.

The previous prime is 21403155349. The next prime is 21403155437. The reversal of 21403155353 is 35355130412.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10178388544 + 11224766809 = 100888^2 + 105947^2 .

It is a cyclic number.

It is not a de Polignac number, because 21403155353 - 2² = 21403155349 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21403125353) 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, 61858658 + ... + 61859003.

It is an arithmetic number, because the mean of its divisors is an integer number (5381718297).

Almost surely, 2^21403155353 is an apocalyptic number.

It is an amenable number.

21403155353 is a deficient number, since it is larger than the sum of its proper divisors (123717835).

21403155353 is a wasteful number, since it uses less digits than its factorization.

21403155353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123717834.

The product of its (nonzero) digits is 27000, while the sum is 32.

Adding to 21403155353 its reverse (35355130412), we get a palindrome (56758285765).

The spelling of 21403155353 in words is "twenty-one billion, four hundred three million, one hundred fifty-five thousand, three hundred fifty-three".