1645513905 has 64 divisors (see below), whose sum is σ = 3177768960. Its totient is φ = 710290944.

The previous prime is 1645513901. The next prime is 1645513931. The reversal of 1645513905 is 5093155461.

It is a happy number.

It is not a de Polignac number, because 1645513905 - 2² = 1645513901 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1645513901) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 691077 + ... + 693453.

It is an arithmetic number, because the mean of its divisors is an integer number (49652640).

Almost surely, 2^1645513905 is an apocalyptic number.

1645513905 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1645513905 is a deficient number, since it is larger than the sum of its proper divisors (1532255055).

1645513905 is a wasteful number, since it uses less digits than its factorization.

1645513905 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2758.

The product of its (nonzero) digits is 81000, while the sum is 39.

The square root of 1645513905 is about 40564.9344261765. The cubic root of 1645513905 is about 1180.5938562567.

The spelling of 1645513905 in words is "one billion, six hundred forty-five million, five hundred thirteen thousand, nine hundred five".