657661421 has 8 divisors (see below), whose sum is σ = 710986080. Its totient is φ = 606207888.

The previous prime is 657661387. The next prime is 657661429. The reversal of 657661421 is 124166756.

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

It is a cyclic number.

It is not a de Polignac number, because 657661421 - 2⁶ = 657661357 is a prime.

It is a super-3 number, since 3×657661421³ (a number of 27 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (657661429) 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, 467051 + ... + 468456.

It is an arithmetic number, because the mean of its divisors is an integer number (88873260).

Almost surely, 2^657661421 is an apocalyptic number.

It is an amenable number.

657661421 is a deficient number, since it is larger than the sum of its proper divisors (53324659).

657661421 is a wasteful number, since it uses less digits than its factorization.

657661421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 935563.

The product of its digits is 60480, while the sum is 38.

The square root of 657661421 is about 25644.9102357563. The cubic root of 657661421 is about 869.6292166413.

The spelling of 657661421 in words is "six hundred fifty-seven million, six hundred sixty-one thousand, four hundred twenty-one".