121999542 has 64 divisors (see below), whose sum is σ = 286433280. Its totient is φ = 33924384.

The previous prime is 121999517. The next prime is 121999583. The reversal of 121999542 is 245999121.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 121999494 and 121999503.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 275173 + ... + 275615.

It is an arithmetic number, because the mean of its divisors is an integer number (4475520).

Almost surely, 2^121999542 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 121999542, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143216640).

121999542 is an abundant number, since it is smaller than the sum of its proper divisors (164433738).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

121999542 is a wasteful number, since it uses less digits than its factorization.

121999542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 617.

The product of its digits is 58320, while the sum is 42.

The square root of 121999542 is about 11045.3402844820. The cubic root of 121999542 is about 495.9669457464.

The spelling of 121999542 in words is "one hundred twenty-one million, nine hundred ninety-nine thousand, five hundred forty-two".