6656492421 has 12 divisors (see below), whose sum is σ = 9656202348. Its totient is φ = 4418614464.

The previous prime is 6656492413. The next prime is 6656492429. The reversal of 6656492421 is 1242946566.

6656492421 is a `hidden beast` number, since 66 + 564 + 9 + 2 + 4 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (6656492413) and next prime (6656492429).

It can be written as a sum of positive squares in 2 ways, for example, as 1628122500 + 5028369921 = 40350^2 + 70911^2 .

It is not a de Polignac number, because 6656492421 - 2³ = 6656492413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6656492429) 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, 1585050 + ... + 1589243.

It is an arithmetic number, because the mean of its divisors is an integer number (804683529).

Almost surely, 2^6656492421 is an apocalyptic number.

It is an amenable number.

6656492421 is a deficient number, since it is larger than the sum of its proper divisors (2999709927).

6656492421 is a wasteful number, since it uses less digits than its factorization.

6656492421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3174532 (or 3174529 counting only the distinct ones).

The product of its digits is 622080, while the sum is 45.

The square root of 6656492421 is about 81587.3300274007. The cubic root of 6656492421 is about 1881.1141371168.

The spelling of 6656492421 in words is "six billion, six hundred fifty-six million, four hundred ninety-two thousand, four hundred twenty-one".