1661964480 has 672 divisors, whose sum is σ = 6789968640. Its totient is φ = 383201280.

The previous prime is 1661964457. The next prime is 1661964487. The reversal of 1661964480 is 844691661.

1661964480 is a `hidden beast` number, since 16 + 6 + 196 + 448 + 0 = 666.

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 (1661964487) 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, 24805407 + ... + 24805473.

It is an arithmetic number, because the mean of its divisors is an integer number (10104120).

Almost surely, 2^1661964480 is an apocalyptic number.

1661964480 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 1661964480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3394984320).

1661964480 is an abundant number, since it is smaller than the sum of its proper divisors (5128004160).

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

1661964480 is a wasteful number, since it uses less digits than its factorization.

1661964480 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 1661964480 is about 40767.1985792500. The cubic root of 1661964480 is about 1184.5150394999.

The spelling of 1661964480 in words is "one billion, six hundred sixty-one million, nine hundred sixty-four thousand, four hundred eighty".