1649351920 has 20 divisors (see below), whose sum is σ = 3834743400. Its totient is φ = 659740736.

The previous prime is 1649351911. The next prime is 1649351929. The reversal of 1649351920 is 291539461.

It is an interprime number because it is at equal distance from previous prime (1649351911) and next prime (1649351929).

It is a tau number, because it is divible by the number of its divisors (20).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1649351929) 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, 10308370 + ... + 10308529.

It is an arithmetic number, because the mean of its divisors is an integer number (191737170).

Almost surely, 2^1649351920 is an apocalyptic number.

1649351920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1649351920 is an abundant number, since it is smaller than the sum of its proper divisors (2185391480).

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

1649351920 is a wasteful number, since it uses less digits than its factorization.

1649351920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20616912 (or 20616906 counting only the distinct ones).

The product of its (nonzero) digits is 58320, while the sum is 40.

The square root of 1649351920 is about 40612.2139263547. The cubic root of 1649351920 is about 1181.5110203209.

The spelling of 1649351920 in words is "one billion, six hundred forty-nine million, three hundred fifty-one thousand, nine hundred twenty".