19811970 has 96 divisors (see below), whose sum is σ = 57013632. Its totient is φ = 4747776.

The previous prime is 19811969. The next prime is 19811971. The reversal of 19811970 is 7911891.

It is an interprime number because it is at equal distance from previous prime (19811969) and next prime (19811971).

It is not an unprimeable number, because it can be changed into a prime (19811971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34909 + ... + 35471.

It is an arithmetic number, because the mean of its divisors is an integer number (593892).

Almost surely, 2^19811970 is an apocalyptic number.

19811970 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 19811970, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28506816).

19811970 is an abundant number, since it is smaller than the sum of its proper divisors (37201662).

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

19811970 is a wasteful number, since it uses less digits than its factorization.

19811970 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616 (or 613 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 36.

The square root of 19811970 is about 4451.0639177617. The cubic root of 19811970 is about 270.5884286017.

The spelling of 19811970 in words is "nineteen million, eight hundred eleven thousand, nine hundred seventy".