1618778421 has 12 divisors (see below), whose sum is σ = 2518099948. Its totient is φ = 996171264.

The previous prime is 1618778407. The next prime is 1618778423. The reversal of 1618778421 is 1248778161.

1618778421 is a `hidden beast` number, since 1 + 618 + 7 + 7 + 8 + 4 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 298909521 + 1319868900 = 17289^2 + 36330^2 .

It is not a de Polignac number, because 1618778421 - 2²⁵ = 1585223989 is a prime.

It is a super-3 number, since 3×1618778421³ (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 (1618778423) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6917740 + ... + 6917973.

Almost surely, 2^1618778421 is an apocalyptic number.

It is an amenable number.

1618778421 is a deficient number, since it is larger than the sum of its proper divisors (899321527).

1618778421 is a wasteful number, since it uses less digits than its factorization.

1618778421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13835732 (or 13835729 counting only the distinct ones).

The product of its digits is 150528, while the sum is 45.

The square root of 1618778421 is about 40234.0455460298. The cubic root of 1618778421 is about 1174.1650131744.

The spelling of 1618778421 in words is "one billion, six hundred eighteen million, seven hundred seventy-eight thousand, four hundred twenty-one".