21435215557 has 8 divisors (see below), whose sum is σ = 24739938432. Its totient is φ = 18191130000.

The previous prime is 21435215551. The next prime is 21435215569. The reversal of 21435215557 is 75551253412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21435215557 - 2¹⁹ = 21434691269 is a prime.

It is a super-4 number, since 4×21435215557⁴ (a number of 42 digits) contains 4444 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 (21435215551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15158569 + ... + 15159982.

It is an arithmetic number, because the mean of its divisors is an integer number (3092492304).

Almost surely, 2^21435215557 is an apocalyptic number.

It is an amenable number.

21435215557 is a deficient number, since it is larger than the sum of its proper divisors (3304722875).

21435215557 is a wasteful number, since it uses less digits than its factorization.

21435215557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30318659.

The product of its digits is 210000, while the sum is 40.

Adding to 21435215557 its reverse (75551253412), we get a palindrome (96986468969).

The spelling of 21435215557 in words is "twenty-one billion, four hundred thirty-five million, two hundred fifteen thousand, five hundred fifty-seven".