21121023420415 has 16 divisors (see below), whose sum is σ = 26615648035008. Its totient is φ = 16059230643456.

The previous prime is 21121023420403. The next prime is 21121023420487. The reversal of 21121023420415 is 51402432012112.

It is a happy number.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21121023420415 is a prime.

It is a Duffinian number.

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, 584889822 + ... + 584925931.

It is an arithmetic number, because the mean of its divisors is an integer number (1663478002188).

Almost surely, 2^{21121023420415} is an apocalyptic number.

21121023420415 is a deficient number, since it is larger than the sum of its proper divisors (5494624614593).

21121023420415 is a wasteful number, since it uses less digits than its factorization.

21121023420415 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1169815938.

The product of its (nonzero) digits is 3840, while the sum is 28.

Adding to 21121023420415 its reverse (51402432012112), we get a palindrome (72523455432527).

The spelling of 21121023420415 in words is "twenty-one trillion, one hundred twenty-one billion, twenty-three million, four hundred twenty thousand, four hundred fifteen".