1640546420 has 12 divisors (see below), whose sum is σ = 3445147524. Its totient is φ = 656218560.

The previous prime is 1640546387. The next prime is 1640546423. The reversal of 1640546420 is 246450461.

It can be written as a sum of positive squares in 2 ways, for example, as 1242703504 + 397842916 = 35252^2 + 19946^2 .

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640546423) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41013641 + ... + 41013680.

It is an arithmetic number, because the mean of its divisors is an integer number (287095627).

Almost surely, 2^1640546420 is an apocalyptic number.

1640546420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640546420 is an abundant number, since it is smaller than the sum of its proper divisors (1804601104).

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

1640546420 is a wasteful number, since it uses less digits than its factorization.

1640546420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82027330 (or 82027328 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 32.

The square root of 1640546420 is about 40503.6593408546. The cubic root of 1640546420 is about 1179.4046647395.

Adding to 1640546420 its reverse (246450461), we get a palindrome (1886996881).

The spelling of 1640546420 in words is "one billion, six hundred forty million, five hundred forty-six thousand, four hundred twenty".