1921939420 has 48 divisors (see below), whose sum is σ = 4281076800. Its totient is φ = 722269184.

The previous prime is 1921939351. The next prime is 1921939427. The reversal of 1921939420 is 249391291.

It is a super-2 number, since 2×1921939420² = 7387702268299872800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921939427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 198942 + ... + 208378.

It is an arithmetic number, because the mean of its divisors is an integer number (89189100).

Almost surely, 2^1921939420 is an apocalyptic number.

1921939420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1921939420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2140538400).

1921939420 is an abundant number, since it is smaller than the sum of its proper divisors (2359137380).

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

1921939420 is a wasteful number, since it uses less digits than its factorization.

1921939420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10062 (or 10060 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 1921939420 is about 43839.9295163667. The cubic root of 1921939420 is about 1243.3113496693.

The spelling of 1921939420 in words is "one billion, nine hundred twenty-one million, nine hundred thirty-nine thousand, four hundred twenty".