215420121 has 40 divisors (see below), whose sum is σ = 372420960. Its totient is φ = 123060168.

The previous prime is 215420113. The next prime is 215420131. The reversal of 215420121 is 121024512.

215420121 is a `hidden beast` number, since 2 + 1 + 542 + 0 + 121 = 666.

It is not a de Polignac number, because 215420121 - 2³ = 215420113 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 215420094 and 215420103.

It is not an unprimeable number, because it can be changed into a prime (215420111) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 63166 + ... + 66488.

It is an arithmetic number, because the mean of its divisors is an integer number (9310524).

Almost surely, 2^215420121 is an apocalyptic number.

215420121 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

215420121 is a deficient number, since it is larger than the sum of its proper divisors (157000839).

215420121 is an frugal number, since it uses more digits than its factorization.

215420121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3360 (or 3333 counting only the distinct ones).

The product of its (nonzero) digits is 160, while the sum is 18.

The square root of 215420121 is about 14677.1973142014. The cubic root of 215420121 is about 599.4625938013.

Adding to 215420121 its reverse (121024512), we get a palindrome (336444633).

The spelling of 215420121 in words is "two hundred fifteen million, four hundred twenty thousand, one hundred twenty-one".