1664551431 has 16 divisors (see below), whose sum is σ = 2467096800. Its totient is φ = 1109208384.

The previous prime is 1664551393. The next prime is 1664551451. The reversal of 1664551431 is 1341554661.

1664551431 is a `hidden beast` number, since 1 + 6 + 64 + 551 + 43 + 1 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-1664551431 is a prime.

It is a super-2 number, since 2×1664551431² = 5541462932888295522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664551451) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 54435 + ... + 79323.

It is an arithmetic number, because the mean of its divisors is an integer number (154193550).

Almost surely, 2^1664551431 is an apocalyptic number.

1664551431 is a deficient number, since it is larger than the sum of its proper divisors (802545369).

1664551431 is a wasteful number, since it uses less digits than its factorization.

1664551431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27375 (or 27369 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 1664551431 is about 40798.9145811503. The cubic root of 1664551431 is about 1185.1293113172.

The spelling of 1664551431 in words is "one billion, six hundred sixty-four million, five hundred fifty-one thousand, four hundred thirty-one".