121520820 has 24 divisors (see below), whose sum is σ = 340258464. Its totient is φ = 32405536.

The previous prime is 121520813. The next prime is 121520821. The reversal of 121520820 is 28025121.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121520821) 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, 1012614 + ... + 1012733.

It is an arithmetic number, because the mean of its divisors is an integer number (14177436).

Almost surely, 2^121520820 is an apocalyptic number.

121520820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

121520820 is an abundant number, since it is smaller than the sum of its proper divisors (218737644).

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

121520820 is a wasteful number, since it uses less digits than its factorization.

121520820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2025359 (or 2025357 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 21.

The square root of 121520820 is about 11023.6482164481. The cubic root of 121520820 is about 495.3173763050.

Adding to 121520820 its reverse (28025121), we get a palindrome (149545941).

The spelling of 121520820 in words is "one hundred twenty-one million, five hundred twenty thousand, eight hundred twenty".