121015551 has 8 divisors (see below), whose sum is σ = 163017904. Its totient is φ = 79845120.

The previous prime is 121015547. The next prime is 121015561. The reversal of 121015551 is 155510121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 121015551 - 2² = 121015547 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 (121015501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 207640 + ... + 208221.

It is an arithmetic number, because the mean of its divisors is an integer number (20377238).

Almost surely, 2^121015551 is an apocalyptic number.

121015551 is a deficient number, since it is larger than the sum of its proper divisors (42002353).

121015551 is an equidigital number, since it uses as much as digits as its factorization.

121015551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415961.

The product of its (nonzero) digits is 250, while the sum is 21.

The square root of 121015551 is about 11000.7068409262. The cubic root of 121015551 is about 494.6299325648.

Adding to 121015551 its reverse (155510121), we get a palindrome (276525672).

It can be divided in two parts, 1210 and 15551, that added together give a palindrome (16761).

The spelling of 121015551 in words is "one hundred twenty-one million, fifteen thousand, five hundred fifty-one".