21551412344 has 64 divisors (see below), whose sum is σ = 52570391040. Its totient is φ = 8031576960.

The previous prime is 21551412341. The next prime is 21551412347. The reversal of 21551412344 is 44321415512.

It is an interprime number because it is at equal distance from previous prime (21551412341) and next prime (21551412347).

It is a super-2 number, since 2×21551412344² (a number of 21 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21551412344.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21551412341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 746399 + ... + 774734.

It is an arithmetic number, because the mean of its divisors is an integer number (821412360).

Almost surely, 2^21551412344 is an apocalyptic number.

It is an amenable number.

21551412344 is an abundant number, since it is smaller than the sum of its proper divisors (31018978696).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21551412344 is a wasteful number, since it uses less digits than its factorization.

21551412344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1521180 (or 1521176 counting only the distinct ones).

The product of its digits is 19200, while the sum is 32.

Adding to 21551412344 its reverse (44321415512), we get a palindrome (65872827856).

The spelling of 21551412344 in words is "twenty-one billion, five hundred fifty-one million, four hundred twelve thousand, three hundred forty-four".