6925128421 has 4 divisors (see below), whose sum is σ = 7112294092. Its totient is φ = 6737962752.

The previous prime is 6925128383. The next prime is 6925128433. The reversal of 6925128421 is 1248215296.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2688941025 + 4236187396 = 51855^2 + 65086^2 .

It is a cyclic number.

It is not a de Polignac number, because 6925128421 - 2⁷ = 6925128293 is a prime.

It is a super-3 number, since 3×6925128421³ (a number of 30 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6925128451) 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, 93582780 + ... + 93582853.

It is an arithmetic number, because the mean of its divisors is an integer number (1778073523).

Almost surely, 2^6925128421 is an apocalyptic number.

It is an amenable number.

6925128421 is a deficient number, since it is larger than the sum of its proper divisors (187165671).

6925128421 is a wasteful number, since it uses less digits than its factorization.

6925128421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187165670.

The product of its digits is 69120, while the sum is 40.

The square root of 6925128421 is about 83217.3564888960. The cubic root of 6925128421 is about 1906.0865221362.

The spelling of 6925128421 in words is "six billion, nine hundred twenty-five million, one hundred twenty-eight thousand, four hundred twenty-one".