261406740 has 48 divisors (see below), whose sum is σ = 836502912. Its totient is φ = 59750016.

The previous prime is 261406729. The next prime is 261406751. The reversal of 261406740 is 47604162.

It is an interprime number because it is at equal distance from previous prime (261406729) and next prime (261406751).

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

It is a junction number, because it is equal to n+sod(n) for n = 261406698 and 261406707.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 310779 + ... + 311618.

It is an arithmetic number, because the mean of its divisors is an integer number (17427144).

Almost surely, 2^261406740 is an apocalyptic number.

261406740 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261406740 is an abundant number, since it is smaller than the sum of its proper divisors (575096172).

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

261406740 is a wasteful number, since it uses less digits than its factorization.

261406740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 622416 (or 622414 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 30.

The square root of 261406740 is about 16168.0778078286. The cubic root of 261406740 is about 639.3994529261.

The spelling of 261406740 in words is "two hundred sixty-one million, four hundred six thousand, seven hundred forty".