21001211021015 has 16 divisors (see below), whose sum is σ = 25450324092000. Its totient is φ = 16635821254272.

The previous prime is 21001211020967. The next prime is 21001211021047. The reversal of 21001211021015 is 51012011210012.

It is a cyclic number.

It is not a de Polignac number, because 21001211021015 - 2⁴⁰ = 19901699393239 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001211020984 and 21001211021002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47677340 + ... + 48115809.

It is an arithmetic number, because the mean of its divisors is an integer number (1590645255750).

Almost surely, 2^{21001211021015} is an apocalyptic number.

21001211021015 is a deficient number, since it is larger than the sum of its proper divisors (4449113070985).

21001211021015 is a wasteful number, since it uses less digits than its factorization.

21001211021015 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95793586.

The product of its (nonzero) digits is 40, while the sum is 17.

Adding to 21001211021015 its reverse (51012011210012), we get a palindrome (72013222231027).

The spelling of 21001211021015 in words is "twenty-one trillion, one billion, two hundred eleven million, twenty-one thousand, fifteen".