121857649 has 4 divisors (see below), whose sum is σ = 129025764. Its totient is φ = 114689536.

The previous prime is 121857629. The next prime is 121857689. The reversal of 121857649 is 946758121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 946758121 = 97 ⋅9760393.

It can be written as a sum of positive squares in 2 ways, for example, as 110250000 + 11607649 = 10500^2 + 3407^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-121857649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (121857629) 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, 3584032 + ... + 3584065.

It is an arithmetic number, because the mean of its divisors is an integer number (32256441).

Almost surely, 2^121857649 is an apocalyptic number.

It is an amenable number.

121857649 is a deficient number, since it is larger than the sum of its proper divisors (7168115).

121857649 is an equidigital number, since it uses as much as digits as its factorization.

121857649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7168114.

The product of its digits is 120960, while the sum is 43.

The square root of 121857649 is about 11038.9152093854. The cubic root of 121857649 is about 495.7745910935.

The spelling of 121857649 in words is "one hundred twenty-one million, eight hundred fifty-seven thousand, six hundred forty-nine".