21612256043 has 16 divisors (see below), whose sum is σ = 26289598464. Its totient is φ = 17343795840.

The previous prime is 21612256031. The next prime is 21612256063. The reversal of 21612256043 is 34065221612.

It is not a de Polignac number, because 21612256043 - 2⁸ = 21612255787 is a prime.

It is a super-2 number, since 2×21612256043² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21612256013) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 452705 + ... + 498162.

It is an arithmetic number, because the mean of its divisors is an integer number (1643099904).

Almost surely, 2^21612256043 is an apocalyptic number.

21612256043 is a deficient number, since it is larger than the sum of its proper divisors (4677342421).

21612256043 is a wasteful number, since it uses less digits than its factorization.

21612256043 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 951082.

The product of its (nonzero) digits is 17280, while the sum is 32.

Adding to 21612256043 its reverse (34065221612), we get a palindrome (55677477655).

The spelling of 21612256043 in words is "twenty-one billion, six hundred twelve million, two hundred fifty-six thousand, forty-three".