1649672640 has 672 divisors, whose sum is σ = 7280672256. Its totient is φ = 332881920.

The previous prime is 1649672603. The next prime is 1649672641. The reversal of 1649672640 is 462769461.

It is a tau number, because it is divible by the number of its divisors (672).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1649672641) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 9535594 + ... + 9535766.

Almost surely, 2^1649672640 is an apocalyptic number.

1649672640 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 1649672640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3640336128).

1649672640 is an abundant number, since it is smaller than the sum of its proper divisors (5630999616).

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

1649672640 is a wasteful number, since it uses less digits than its factorization.

1649672640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 435456, while the sum is 45.

The square root of 1649672640 is about 40616.1623002469. The cubic root of 1649672640 is about 1181.5875978038.

The spelling of 1649672640 in words is "one billion, six hundred forty-nine million, six hundred seventy-two thousand, six hundred forty".