121689405 has 16 divisors (see below), whose sum is σ = 216336960. Its totient is φ = 64900944.

The previous prime is 121689401. The next prime is 121689409. The reversal of 121689405 is 504986121.

It is an interprime number because it is at equal distance from previous prime (121689401) and next prime (121689409).

It is not a de Polignac number, because 121689405 - 2² = 121689401 is a prime.

It is a super-2 number, since 2×121689405² = 29616622578508050, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 121689405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121689401) 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, 450567 + ... + 450836.

It is an arithmetic number, because the mean of its divisors is an integer number (13521060).

Almost surely, 2^121689405 is an apocalyptic number.

121689405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

121689405 is a deficient number, since it is larger than the sum of its proper divisors (94647555).

121689405 is an equidigital number, since it uses as much as digits as its factorization.

121689405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 901417 (or 901411 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 121689405 is about 11031.2920820727. The cubic root of 121689405 is about 495.5463205994.

The spelling of 121689405 in words is "one hundred twenty-one million, six hundred eighty-nine thousand, four hundred five".