1664766520 has 32 divisors (see below), whose sum is σ = 3756870000. Its totient is φ = 663925248.

The previous prime is 1664766503. The next prime is 1664766527. The reversal of 1664766520 is 256674661.

It is a happy number.

It is a super-2 number, since 2×1664766520² = 5542895132225820800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664766527) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48270 + ... + 75229.

Almost surely, 2^1664766520 is an apocalyptic number.

1664766520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1664766520 is an abundant number, since it is smaller than the sum of its proper divisors (2092103480).

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

1664766520 is a wasteful number, since it uses less digits than its factorization.

1664766520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123847 (or 123843 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 43.

The square root of 1664766520 is about 40801.5504607362. The cubic root of 1664766520 is about 1185.1803555595.

The spelling of 1664766520 in words is "one billion, six hundred sixty-four million, seven hundred sixty-six thousand, five hundred twenty".