21719841506 has 16 divisors (see below), whose sum is σ = 35581841568. Its totient is φ = 9861465600.

The previous prime is 21719841503. The next prime is 21719841569. The reversal of 21719841506 is 60514891712.

21719841506 = 495² + 496² + ... + 4026².

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21719841503) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 539615 + ... + 578466.

It is an arithmetic number, because the mean of its divisors is an integer number (2223865098).

Almost surely, 2^21719841506 is an apocalyptic number.

21719841506 is a deficient number, since it is larger than the sum of its proper divisors (13862000062).

21719841506 is a wasteful number, since it uses less digits than its factorization.

21719841506 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1118977.

The product of its (nonzero) digits is 120960, while the sum is 44.

The spelling of 21719841506 in words is "twenty-one billion, seven hundred nineteen million, eight hundred forty-one thousand, five hundred six".