1640847621 has 64 divisors (see below), whose sum is σ = 2670491648. Its totient is φ = 876572928.

The previous prime is 1640847589. The next prime is 1640847661. The reversal of 1640847621 is 1267480461.

It is not a de Polignac number, because 1640847621 - 2⁵ = 1640847589 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1640847621.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640847661) 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, 2238171 + ... + 2238903.

It is an arithmetic number, because the mean of its divisors is an integer number (41726432).

Almost surely, 2^1640847621 is an apocalyptic number.

It is an amenable number.

1640847621 is a deficient number, since it is larger than the sum of its proper divisors (1029644027).

1640847621 is a wasteful number, since it uses less digits than its factorization.

1640847621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 890.

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 1640847621 is about 40507.3773651171. The cubic root of 1640847621 is about 1179.4768390919.

The spelling of 1640847621 in words is "one billion, six hundred forty million, eight hundred forty-seven thousand, six hundred twenty-one".