121231645 has 4 divisors (see below), whose sum is σ = 145477980. Its totient is φ = 96985312.

The previous prime is 121231637. The next prime is 121231657. The reversal of 121231645 is 546132121.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 37380996 + 83850649 = 6114^2 + 9157^2 .

It is a cyclic number.

It is not a de Polignac number, because 121231645 - 2³ = 121231637 is a prime.

It is a super-2 number, since 2×121231645² = 29394223498812050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12123160 + ... + 12123169.

It is an arithmetic number, because the mean of its divisors is an integer number (36369495).

Almost surely, 2^121231645 is an apocalyptic number.

It is an amenable number.

121231645 is a deficient number, since it is larger than the sum of its proper divisors (24246335).

121231645 is an equidigital number, since it uses as much as digits as its factorization.

121231645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24246334.

The product of its digits is 1440, while the sum is 25.

The square root of 121231645 is about 11010.5242836116. The cubic root of 121231645 is about 494.9241729920.

Adding to 121231645 its reverse (546132121), we get a palindrome (667363766).

The spelling of 121231645 in words is "one hundred twenty-one million, two hundred thirty-one thousand, six hundred forty-five".