121287643 has 4 divisors (see below), whose sum is σ = 121701888. Its totient is φ = 120873400.

The previous prime is 121287631. The next prime is 121287709. The reversal of 121287643 is 346782121.

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 121287643 - 2²⁵ = 87733211 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121287599 and 121287608.

It is not an unprimeable number, because it can be changed into a prime (121287743) 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, 206683 + ... + 207268.

It is an arithmetic number, because the mean of its divisors is an integer number (30425472).

Almost surely, 2^121287643 is an apocalyptic number.

121287643 is a deficient number, since it is larger than the sum of its proper divisors (414245).

121287643 is an equidigital number, since it uses as much as digits as its factorization.

121287643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 414244.

The product of its digits is 16128, while the sum is 34.

The square root of 121287643 is about 11013.0669207083. The cubic root of 121287643 is about 495.0003645884. Note that the first 3 decimals are identical.

The spelling of 121287643 in words is "one hundred twenty-one million, two hundred eighty-seven thousand, six hundred forty-three".