261426978 has 54 divisors (see below), whose sum is σ = 587854449. Its totient is φ = 83963952.

The previous prime is 261426959. The next prime is 261426983. The reversal of 261426978 is 879624162.

It is a happy number.

261426978 is a `hidden beast` number, since 2 + 614 + 26 + 9 + 7 + 8 = 666.

261426978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 210917529 + 50509449 = 14523^2 + 7107^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=11433.

Its product of digits (290304) is a multiple of the sum of its prime factors (288).

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 2538075 + ... + 2538177.

Almost surely, 2^261426978 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261426978

261426978 is an abundant number, since it is smaller than the sum of its proper divisors (326427471).

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

261426978 is a wasteful number, since it uses less digits than its factorization.

261426978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 145 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 261426978 is about 16168.7036586116. The cubic root of 261426978 is about 639.4159531793.

It can be divided in two parts, 2614 and 26978, that added together give a palindrome (29592).

The spelling of 261426978 in words is "two hundred sixty-one million, four hundred twenty-six thousand, nine hundred seventy-eight".