3891897720 has 256 divisors, whose sum is σ = 13911004800. Its totient is φ = 976416768.

The previous prime is 3891897719. The next prime is 3891897721. The reversal of 3891897720 is 277981983.

It is an interprime number because it is at equal distance from previous prime (3891897719) and next prime (3891897721).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3891897721) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1485852 + ... + 1488468.

Almost surely, 2^3891897720 is an apocalyptic number.

3891897720 is a gapful number since it is divisible by the number (30) 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 3891897720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6955502400).

3891897720 is an abundant number, since it is smaller than the sum of its proper divisors (10019107080).

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

3891897720 is a wasteful number, since it uses less digits than its factorization.

3891897720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2666 (or 2644 counting only the distinct ones).

The product of its (nonzero) digits is 1524096, while the sum is 54.

The square root of 3891897720 is about 62385.0760999776. The cubic root of 3891897720 is about 1572.9701196818.

The spelling of 3891897720 in words is "three billion, eight hundred ninety-one million, eight hundred ninety-seven thousand, seven hundred twenty".