21554021434 has 16 divisors (see below), whose sum is σ = 36407966976. Its totient is φ = 9481240800.

The previous prime is 21554021431. The next prime is 21554021449. The reversal of 21554021434 is 43412045512.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a junction number, because it is equal to n+sod(n) for n = 21554021396 and 21554021405.

It is not an unprimeable number, because it can be changed into a prime (21554021431) 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 7 ways as a sum of consecutive naturals, for example, 15801387 + ... + 15802750.

It is an arithmetic number, because the mean of its divisors is an integer number (2275497936).

Almost surely, 2^21554021434 is an apocalyptic number.

21554021434 is a deficient number, since it is larger than the sum of its proper divisors (14853945542).

21554021434 is a wasteful number, since it uses less digits than its factorization.

21554021434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31604181.

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 21554021434 its reverse (43412045512), we get a palindrome (64966066946).

The spelling of 21554021434 in words is "twenty-one billion, five hundred fifty-four million, twenty-one thousand, four hundred thirty-four".