1640785477 has 8 divisors (see below), whose sum is σ = 1713838464. Its totient is φ = 1567875408.

The previous prime is 1640785427. The next prime is 1640785493. The reversal of 1640785477 is 7745870461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1640785477 - 2²³ = 1632396869 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 1640785477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640785427) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11913 + ... + 58510.

It is an arithmetic number, because the mean of its divisors is an integer number (214229808).

Almost surely, 2^1640785477 is an apocalyptic number.

It is an amenable number.

1640785477 is a deficient number, since it is larger than the sum of its proper divisors (73052987).

1640785477 is a wasteful number, since it uses less digits than its factorization.

1640785477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71459.

The product of its (nonzero) digits is 1317120, while the sum is 49.

The square root of 1640785477 is about 40506.6102877049. The cubic root of 1640785477 is about 1179.4619487525.

The spelling of 1640785477 in words is "one billion, six hundred forty million, seven hundred eighty-five thousand, four hundred seventy-seven".