15491294640 has 120 divisors (see below), whose sum is σ = 52111285200. Its totient is φ = 4124155392.

The previous prime is 15491294597. The next prime is 15491294641. The reversal of 15491294640 is 4649219451.

15491294640 is a `hidden beast` number, since 1 + 549 + 1 + 29 + 46 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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 (15491294641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 423811 + ... + 458909.

It is an arithmetic number, because the mean of its divisors is an integer number (434260710).

Almost surely, 2^15491294640 is an apocalyptic number.

15491294640 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 15491294640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26055642600).

15491294640 is an abundant number, since it is smaller than the sum of its proper divisors (36619990560).

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

15491294640 is a wasteful number, since it uses less digits than its factorization.

15491294640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35731 (or 35722 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 45.

The spelling of 15491294640 in words is "fifteen billion, four hundred ninety-one million, two hundred ninety-four thousand, six hundred forty".