15666420 has 96 divisors (see below), whose sum is σ = 54706176. Its totient is φ = 3254400.

The previous prime is 15666397. The next prime is 15666451. The reversal of 15666420 is 2466651.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2925 + ... + 6315.

It is an arithmetic number, because the mean of its divisors is an integer number (569856).

Almost surely, 2^15666420 is an apocalyptic number.

15666420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 15666420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27353088).

15666420 is an abundant number, since it is smaller than the sum of its proper divisors (39039756).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

15666420 is a wasteful number, since it uses less digits than its factorization.

15666420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3421 (or 3419 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 15666420 is about 3958.0828692689. The cubic root of 15666420 is about 250.2207117546.

It can be divided in two parts, 15 and 666420, that added together give a triangular number (666435 = T₁₁₅₄).

The spelling of 15666420 in words is "fifteen million, six hundred sixty-six thousand, four hundred twenty".