1640020797 has 32 divisors (see below), whose sum is σ = 2452147200. Its totient is φ = 1083278016.

The previous prime is 1640020783. The next prime is 1640020859. The reversal of 1640020797 is 7970200461.

It is a happy number.

1640020797 is a `hidden beast` number, since 1 + 640 + 0 + 2 + 0 + 7 + 9 + 7 = 666.

It is not a de Polignac number, because 1640020797 - 2¹⁵ = 1639988029 is a prime.

It is a super-3 number, since 3×1640020797³ (a number of 29 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640020717) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2237043 + ... + 2237775.

It is an arithmetic number, because the mean of its divisors is an integer number (76629600).

Almost surely, 2^1640020797 is an apocalyptic number.

It is an amenable number.

1640020797 is a deficient number, since it is larger than the sum of its proper divisors (812126403).

1640020797 is a wasteful number, since it uses less digits than its factorization.

1640020797 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1394 (or 1388 counting only the distinct ones).

The product of its (nonzero) digits is 21168, while the sum is 36.

The square root of 1640020797 is about 40497.1702344744. The cubic root of 1640020797 is about 1179.2786928013.

The spelling of 1640020797 in words is "one billion, six hundred forty million, twenty thousand, seven hundred ninety-seven".