21364432655 has 8 divisors (see below), whose sum is σ = 25638625872. Its totient is φ = 17090675008.

The previous prime is 21364432631. The next prime is 21364432679. The reversal of 21364432655 is 55623446312.

It is an interprime number because it is at equal distance from previous prime (21364432631) and next prime (21364432679).

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 21364432655 - 2⁶ = 21364432591 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11027 + ... + 207003.

It is an arithmetic number, because the mean of its divisors is an integer number (3204828234).

Almost surely, 2^21364432655 is an apocalyptic number.

21364432655 is a deficient number, since it is larger than the sum of its proper divisors (4274193217).

21364432655 is a wasteful number, since it uses less digits than its factorization.

21364432655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 217785.

The product of its digits is 518400, while the sum is 41.

Adding to 21364432655 its reverse (55623446312), we get a palindrome (76987878967).

The spelling of 21364432655 in words is "twenty-one billion, three hundred sixty-four million, four hundred thirty-two thousand, six hundred fifty-five".