21015007102 has 4 divisors (see below), whose sum is σ = 31522510656. Its totient is φ = 10507503550.

The previous prime is 21015007087. The next prime is 21015007121. The reversal of 21015007102 is 20170051012.

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

It is a super-2 number, since 2×21015007102² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21015007102.

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, 5253751774 + ... + 5253751777.

It is an arithmetic number, because the mean of its divisors is an integer number (7880627664).

Almost surely, 2^21015007102 is an apocalyptic number.

21015007102 is a deficient number, since it is larger than the sum of its proper divisors (10507503554).

21015007102 is a wasteful number, since it uses less digits than its factorization.

21015007102 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10507503553.

The product of its (nonzero) digits is 140, while the sum is 19.

Adding to 21015007102 its reverse (20170051012), we get a palindrome (41185058114).

The spelling of 21015007102 in words is "twenty-one billion, fifteen million, seven thousand, one hundred two".