21551402401215 has 32 divisors (see below), whose sum is σ = 35981920396800. Its totient is φ = 10994201556096.

The previous prime is 21551402401121. The next prime is 21551402401237. The reversal of 21551402401215 is 51210420415512.

It is not a de Polignac number, because 21551402401215 - 2¹⁶ = 21551402335679 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 30983061 + ... + 31671009.

It is an arithmetic number, because the mean of its divisors is an integer number (1124435012400).

Almost surely, 2^{21551402401215} is an apocalyptic number.

21551402401215 is a deficient number, since it is larger than the sum of its proper divisors (14430517995585).

21551402401215 is a wasteful number, since it uses less digits than its factorization.

21551402401215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778783.

The product of its (nonzero) digits is 16000, while the sum is 33.

Adding to 21551402401215 its reverse (51210420415512), we get a palindrome (72761822816727).

The spelling of 21551402401215 in words is "twenty-one trillion, five hundred fifty-one billion, four hundred two million, four hundred one thousand, two hundred fifteen".