6561390 has 64 divisors (see below), whose sum is σ = 17521920. Its totient is φ = 1559040.

The previous prime is 6561383. The next prime is 6561427. The reversal of 6561390 is 931656.

It is a happy number.

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, 19302 + ... + 19638.

It is an arithmetic number, because the mean of its divisors is an integer number (273780).

Almost surely, 2^6561390 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6561390, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8760960).

6561390 is an abundant number, since it is smaller than the sum of its proper divisors (10960530).

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

6561390 is a wasteful number, since it uses less digits than its factorization.

6561390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417.

The product of its (nonzero) digits is 4860, while the sum is 30.

The square root of 6561390 is about 2561.5210325117. The cubic root of 6561390 is about 187.2112533413.

It can be divided in two parts, 65613 and 90, that added together give a triangular number (65703 = T₃₆₂).

The spelling of 6561390 in words is "six million, five hundred sixty-one thousand, three hundred ninety".