30121920 has 84 divisors (see below), whose sum is σ = 103616760. Its totient is φ = 8031744.

The previous prime is 30121907. The next prime is 30121951. The reversal of 30121920 is 2912103.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 30121893 and 30121902.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2350 + ... + 8109.

Almost surely, 2^30121920 is an apocalyptic number.

30121920 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

30121920 is an abundant number, since it is smaller than the sum of its proper divisors (73494840).

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

30121920 is a wasteful number, since it uses less digits than its factorization.

30121920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10482 (or 10469 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

The square root of 30121920 is about 5488.3440125415. The cubic root of 30121920 is about 311.1436080945.

The spelling of 30121920 in words is "thirty million, one hundred twenty-one thousand, nine hundred twenty".