391868730 has 192 divisors, whose sum is σ = 1188794880. Its totient is φ = 88560000.

The previous prime is 391868723. The next prime is 391868731. The reversal of 391868730 is 37868193.

It is a happy number.

It is a super-2 number, since 2×391868730² = 307122203103625800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (391868731) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1561105 + ... + 1561355.

It is an arithmetic number, because the mean of its divisors is an integer number (6191640).

Almost surely, 2^391868730 is an apocalyptic number.

391868730 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 391868730, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (594397440).

391868730 is an abundant number, since it is smaller than the sum of its proper divisors (796926150).

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

391868730 is a wasteful number, since it uses less digits than its factorization.

391868730 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 377 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The square root of 391868730 is about 19795.6745275325. The cubic root of 391868730 is about 731.7794395063.

The spelling of 391868730 in words is "three hundred ninety-one million, eight hundred sixty-eight thousand, seven hundred thirty".