1664891025 has 48 divisors (see below), whose sum is σ = 3178379904. Its totient is φ = 753223680.

The previous prime is 1664891023. The next prime is 1664891027. The reversal of 1664891025 is 5201984661.

It is an interprime number because it is at equal distance from previous prime (1664891023) and next prime (1664891027).

It is not a de Polignac number, because 1664891025 - 2¹ = 1664891023 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1664891023) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 34579 + ... + 67271.

It is an arithmetic number, because the mean of its divisors is an integer number (66216248).

Almost surely, 2^1664891025 is an apocalyptic number.

1664891025 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664891025 is a deficient number, since it is larger than the sum of its proper divisors (1513488879).

1664891025 is a wasteful number, since it uses less digits than its factorization.

1664891025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32810 (or 32805 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 42.

The square root of 1664891025 is about 40803.0761707987. The cubic root of 1664891025 is about 1185.2099006839.

The spelling of 1664891025 in words is "one billion, six hundred sixty-four million, eight hundred ninety-one thousand, twenty-five".