661334421 has 32 divisors (see below), whose sum is σ = 985310208. Its totient is φ = 391184640.

The previous prime is 661334419. The next prime is 661334423. The reversal of 661334421 is 124433166.

It is an interprime number because it is at equal distance from previous prime (661334419) and next prime (661334423).

It is not a de Polignac number, because 661334421 - 2¹ = 661334419 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661334423) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 248520 + ... + 251166.

It is an arithmetic number, because the mean of its divisors is an integer number (30790944).

Almost surely, 2^661334421 is an apocalyptic number.

It is an amenable number.

661334421 is a deficient number, since it is larger than the sum of its proper divisors (323975787).

661334421 is a wasteful number, since it uses less digits than its factorization.

661334421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2841.

The product of its digits is 10368, while the sum is 30.

The square root of 661334421 is about 25716.4231766395. The cubic root of 661334421 is about 871.2451545777.

Adding to 661334421 its reverse (124433166), we get a palindrome (785767587).

The spelling of 661334421 in words is "six hundred sixty-one million, three hundred thirty-four thousand, four hundred twenty-one".