1655747421 has 4 divisors (see below), whose sum is σ = 2207663232. Its totient is φ = 1103831612.

The previous prime is 1655747413. The next prime is 1655747449. The reversal of 1655747421 is 1247475561.

1655747421 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1247475561 = 3 ⋅415825187.

It is a cyclic number.

It is not a de Polignac number, because 1655747421 - 2³ = 1655747413 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1655747221) 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, 275957901 + ... + 275957906.

It is an arithmetic number, because the mean of its divisors is an integer number (551915808).

Almost surely, 2^1655747421 is an apocalyptic number.

It is an amenable number.

1655747421 is a deficient number, since it is larger than the sum of its proper divisors (551915811).

1655747421 is an equidigital number, since it uses as much as digits as its factorization.

1655747421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 551915810.

The product of its digits is 235200, while the sum is 42.

The square root of 1655747421 is about 40690.8763852537. The cubic root of 1655747421 is about 1183.0361868636.

The spelling of 1655747421 in words is "one billion, six hundred fifty-five million, seven hundred forty-seven thousand, four hundred twenty-one".