121415815 has 4 divisors (see below), whose sum is σ = 145698984. Its totient is φ = 97132648.

The previous prime is 121415813. The next prime is 121415821. The reversal of 121415815 is 518514121.

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

It is a cyclic number.

It is not a de Polignac number, because 121415815 - 2¹ = 121415813 is a prime.

It is a super-2 number, since 2×121415815² = 29483600264228450, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121415813) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12141577 + ... + 12141586.

It is an arithmetic number, because the mean of its divisors is an integer number (36424746).

Almost surely, 2^121415815 is an apocalyptic number.

121415815 is a deficient number, since it is larger than the sum of its proper divisors (24283169).

121415815 is an equidigital number, since it uses as much as digits as its factorization.

121415815 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24283168.

The product of its digits is 1600, while the sum is 28.

The square root of 121415815 is about 11018.8844716695. The cubic root of 121415815 is about 495.1746688277.

Adding to 121415815 its reverse (518514121), we get a palindrome (639929936).

It can be divided in two parts, 12141 and 5815, that added together give a square (17956 = 134²).

The spelling of 121415815 in words is "one hundred twenty-one million, four hundred fifteen thousand, eight hundred fifteen".