261549420 has 96 divisors (see below), whose sum is σ = 845945856. Its totient is φ = 59673600.

The previous prime is 261549397. The next prime is 261549427. The reversal of 261549420 is 24945162.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (261549427) 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, 436 + ... + 22875.

It is an arithmetic number, because the mean of its divisors is an integer number (8811936).

Almost surely, 2^261549420 is an apocalyptic number.

261549420 is a gapful number since it is divisible by the number (20) 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 261549420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (422972928).

261549420 is an abundant number, since it is smaller than the sum of its proper divisors (584396436).

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

261549420 is a wasteful number, since it uses less digits than its factorization.

261549420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23351 (or 23349 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 33.

The square root of 261549420 is about 16172.4896042632. The cubic root of 261549420 is about 639.5157632665.

The spelling of 261549420 in words is "two hundred sixty-one million, five hundred forty-nine thousand, four hundred twenty".