121639739 has 4 divisors (see below), whose sum is σ = 130996656. Its totient is φ = 112282824.

The previous prime is 121639723. The next prime is 121639751. The reversal of 121639739 is 937936121.

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 121639739 - 2⁴ = 121639723 is a prime.

It is a super-2 number, since 2×121639739² = 29592452207976242, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 121639696 and 121639705.

It is not an unprimeable number, because it can be changed into a prime (121639789) 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, 4678439 + ... + 4678464.

It is an arithmetic number, because the mean of its divisors is an integer number (32749164).

Almost surely, 2^121639739 is an apocalyptic number.

121639739 is a deficient number, since it is larger than the sum of its proper divisors (9356917).

121639739 is an equidigital number, since it uses as much as digits as its factorization.

121639739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9356916.

The product of its digits is 61236, while the sum is 41.

The square root of 121639739 is about 11029.0407107781. The cubic root of 121639739 is about 495.4788944264.

The spelling of 121639739 in words is "one hundred twenty-one million, six hundred thirty-nine thousand, seven hundred thirty-nine".