21312020102 has 4 divisors (see below), whose sum is σ = 31968030156. Its totient is φ = 10656010050.

The previous prime is 21312020101. The next prime is 21312020137. The reversal of 21312020102 is 20102021312.

It is a happy number.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312020101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5328005024 + ... + 5328005027.

It is an arithmetic number, because the mean of its divisors is an integer number (7992007539).

Almost surely, 2^21312020102 is an apocalyptic number.

21312020102 is a deficient number, since it is larger than the sum of its proper divisors (10656010054).

21312020102 is a wasteful number, since it uses less digits than its factorization.

21312020102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10656010053.

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21312020102 its reverse (20102021312), we get a palindrome (41414041414).

The spelling of 21312020102 in words is "twenty-one billion, three hundred twelve million, twenty thousand, one hundred two".