121665550 has 48 divisors (see below), whose sum is σ = 241234560. Its totient is φ = 45519840.

The previous prime is 121665547. The next prime is 121665553. The reversal of 121665550 is 55566121.

It is an interprime number because it is at equal distance from previous prime (121665547) and next prime (121665553).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121665553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 78079 + ... + 79621.

It is an arithmetic number, because the mean of its divisors is an integer number (5025720).

Almost surely, 2^121665550 is an apocalyptic number.

121665550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

121665550 is a deficient number, since it is larger than the sum of its proper divisors (119569010).

121665550 is a wasteful number, since it uses less digits than its factorization.

121665550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1657 (or 1652 counting only the distinct ones).

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 121665550 is about 11030.2107867438. The cubic root of 121665550 is about 495.5139375282.

It can be divided in two parts, 1216 and 65550, that added together give a palindrome (66766).

The spelling of 121665550 in words is "one hundred twenty-one million, six hundred sixty-five thousand, five hundred fifty".