1991415929490 has 288 divisors, whose sum is σ = 6105218184000. Its totient is φ = 448379463168.

The previous prime is 1991415929467. The next prime is 1991415929521. The reversal of 1991415929490 is 949295141991.

It is a happy number.

1991415929490 is a `hidden beast` number, since 1 + 9 + 91 + 4 + 1 + 59 + 2 + 9 + 490 = 666.

It is a hoax number, since the sum of its digits (63) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 8261901 + ... + 8499519.

It is an arithmetic number, because the mean of its divisors is an integer number (21198674250).

Almost surely, 2^{1991415929490} is an apocalyptic number.

1991415929490 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 1991415929490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3052609092000).

1991415929490 is an abundant number, since it is smaller than the sum of its proper divisors (4113802254510).

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

1991415929490 is a wasteful number, since it uses less digits than its factorization.

1991415929490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 237706 (or 237690 counting only the distinct ones).

The product of its (nonzero) digits is 9447840, while the sum is 63.

The spelling of 1991415929490 in words is "one trillion, nine hundred ninety-one billion, four hundred fifteen million, nine hundred twenty-nine thousand, four hundred ninety".