21213103551 has 8 divisors (see below), whose sum is σ = 29048574384. Its totient is φ = 13759850880.

The previous prime is 21213103547. The next prime is 21213103567. The reversal of 21213103551 is 15530131212.

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

It is not a de Polignac number, because 21213103551 - 2² = 21213103547 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21213103151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 95554410 + ... + 95554631.

It is an arithmetic number, because the mean of its divisors is an integer number (3631071798).

Almost surely, 2^21213103551 is an apocalyptic number.

21213103551 is a deficient number, since it is larger than the sum of its proper divisors (7835470833).

21213103551 is a wasteful number, since it uses less digits than its factorization.

21213103551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191109081.

The product of its (nonzero) digits is 900, while the sum is 24.

Adding to 21213103551 its reverse (15530131212), we get a palindrome (36743234763).

The spelling of 21213103551 in words is "twenty-one billion, two hundred thirteen million, one hundred three thousand, five hundred fifty-one".