121720765 has 16 divisors (see below), whose sum is σ = 156169728. Its totient is φ = 90752256.

The previous prime is 121720763. The next prime is 121720769. The reversal of 121720765 is 567027121.

It is not a de Polignac number, because 121720765 - 2¹ = 121720763 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121720763) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1804 + ... + 15706.

It is an arithmetic number, because the mean of its divisors is an integer number (9760608).

Almost surely, 2^121720765 is an apocalyptic number.

It is an amenable number.

121720765 is a deficient number, since it is larger than the sum of its proper divisors (34448963).

121720765 is a wasteful number, since it uses less digits than its factorization.

121720765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14028.

The product of its (nonzero) digits is 5880, while the sum is 31.

The square root of 121720765 is about 11032.7134015164. The cubic root of 121720765 is about 495.5888852414.

Adding to 121720765 its reverse (567027121), we get a palindrome (688747886).

The spelling of 121720765 in words is "one hundred twenty-one million, seven hundred twenty thousand, seven hundred sixty-five".