661269421 has 4 divisors (see below), whose sum is σ = 669640000. Its totient is φ = 652898844.

The previous prime is 661269419. The next prime is 661269473. The reversal of 661269421 is 124962166.

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.

It is a cyclic number.

It is not a de Polignac number, because 661269421 - 2¹ = 661269419 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661269121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4185171 + ... + 4185328.

It is an arithmetic number, because the mean of its divisors is an integer number (167410000).

Almost surely, 2^661269421 is an apocalyptic number.

It is an amenable number.

661269421 is a deficient number, since it is larger than the sum of its proper divisors (8370579).

661269421 is an equidigital number, since it uses as much as digits as its factorization.

661269421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8370578.

The product of its digits is 31104, while the sum is 37.

The square root of 661269421 is about 25715.1593617461. The cubic root of 661269421 is about 871.2166098714.

The spelling of 661269421 in words is "six hundred sixty-one million, two hundred sixty-nine thousand, four hundred twenty-one".