1021121415555 has 128 divisors (see below), whose sum is σ = 1804768542720. Its totient is φ = 491264632320.

The previous prime is 1021121415551. The next prime is 1021121415563. The reversal of 1021121415555 is 5555141211201.

It is a happy number.

It is not a de Polignac number, because 1021121415555 - 2² = 1021121415551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1021121415551) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 268502284 + ... + 268506086.

It is an arithmetic number, because the mean of its divisors is an integer number (14099754240).

Almost surely, 2^{1021121415555} is an apocalyptic number.

1021121415555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1021121415555 is a deficient number, since it is larger than the sum of its proper divisors (783647127165).

1021121415555 is a wasteful number, since it uses less digits than its factorization.

1021121415555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4481.

The product of its (nonzero) digits is 10000, while the sum is 33.

Adding to 1021121415555 its reverse (5555141211201), we get a palindrome (6576262626756).

The spelling of 1021121415555 in words is "one trillion, twenty-one billion, one hundred twenty-one million, four hundred fifteen thousand, five hundred fifty-five".