261535478990 has 32 divisors (see below), whose sum is σ = 495727395840. Its totient is φ = 99070884000.

The previous prime is 261535478969. The next prime is 261535478993. The reversal of 261535478990 is 99874535162.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261535478993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 249815 + ... + 765165.

It is an arithmetic number, because the mean of its divisors is an integer number (15491481120).

It is a 1-persistent number, because it is pandigital, but 2⋅261535478990 = 523070957980 is not.

Almost surely, 2^261535478990 is an apocalyptic number.

261535478990 is a deficient number, since it is larger than the sum of its proper divisors (234191916850).

261535478990 is a wasteful number, since it uses less digits than its factorization.

261535478990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518048.

The product of its (nonzero) digits is 16329600, while the sum is 59.

The spelling of 261535478990 in words is "two hundred sixty-one billion, five hundred thirty-five million, four hundred seventy-eight thousand, nine hundred ninety".