21005543546 has 32 divisors (see below), whose sum is σ = 35906105088. Its totient is φ = 9142721280.

The previous prime is 21005543521. The next prime is 21005543551. The reversal of 21005543546 is 64534550012.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 204911 + ... + 289826.

It is an arithmetic number, because the mean of its divisors is an integer number (1122065784).

Almost surely, 2^21005543546 is an apocalyptic number.

21005543546 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

21005543546 is a deficient number, since it is larger than the sum of its proper divisors (14900561542).

21005543546 is a wasteful number, since it uses less digits than its factorization.

21005543546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 494846.

The product of its (nonzero) digits is 72000, while the sum is 35.

The spelling of 21005543546 in words is "twenty-one billion, five million, five hundred forty-three thousand, five hundred forty-six".