20821248687371 has 4 divisors (see below), whose sum is σ = 22714089477144. Its totient is φ = 18928407897600.

The previous prime is 20821248687361. The next prime is 20821248687413. The reversal of 20821248687371 is 17378684212802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20821248687371 - 2⁶ = 20821248687307 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20821248687371.

It is not an unprimeable number, because it can be changed into a prime (20821248687341) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 946420394870 + ... + 946420394891.

It is an arithmetic number, because the mean of its divisors is an integer number (5678522369286).

Almost surely, 2^{20821248687371} is an apocalyptic number.

20821248687371 is a deficient number, since it is larger than the sum of its proper divisors (1892840789773).

20821248687371 is a wasteful number, since it uses less digits than its factorization.

20821248687371 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1892840789772.

The product of its (nonzero) digits is 14450688, while the sum is 59.

The spelling of 20821248687371 in words is "twenty trillion, eight hundred twenty-one billion, two hundred forty-eight million, six hundred eighty-seven thousand, three hundred seventy-one".