21001523211782 has 4 divisors (see below), whose sum is σ = 31502284817676. Its totient is φ = 10500761605890.

The previous prime is 21001523211751. The next prime is 21001523211829. The reversal of 21001523211782 is 28711232510012.

It is a happy number.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5250380802944 + ... + 5250380802947.

It is an arithmetic number, because the mean of its divisors is an integer number (7875571204419).

Almost surely, 2^{21001523211782} is an apocalyptic number.

21001523211782 is a deficient number, since it is larger than the sum of its proper divisors (10500761605894).

21001523211782 is a wasteful number, since it uses less digits than its factorization.

21001523211782 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10500761605893.

The product of its (nonzero) digits is 13440, while the sum is 35.

Adding to 21001523211782 its reverse (28711232510012), we get a palindrome (49712755721794).

The spelling of 21001523211782 in words is "twenty-one trillion, one billion, five hundred twenty-three million, two hundred eleven thousand, seven hundred eighty-two".