669542421 has 8 divisors (see below), whose sum is σ = 892886080. Its totient is φ = 446280192.

The previous prime is 669542413. The next prime is 669542429. The reversal of 669542421 is 124245966.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (669542413) and next prime (669542429).

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

It is not a de Polignac number, because 669542421 - 2³ = 669542413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 669542421.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (669542429) 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, 2496 + ... + 36678.

It is an arithmetic number, because the mean of its divisors is an integer number (111610760).

Almost surely, 2^669542421 is an apocalyptic number.

It is an amenable number.

669542421 is a deficient number, since it is larger than the sum of its proper divisors (223343659).

669542421 is a wasteful number, since it uses less digits than its factorization.

669542421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40715.

The product of its digits is 103680, while the sum is 39.

The square root of 669542421 is about 25875.5177919206. The cubic root of 669542421 is about 874.8347643362.

The spelling of 669542421 in words is "six hundred sixty-nine million, five hundred forty-two thousand, four hundred twenty-one".