26401561 has 8 divisors (see below), whose sum is σ = 28020384. Its totient is φ = 24790080.

The previous prime is 26401559. The next prime is 26401567. The reversal of 26401561 is 16510462.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 26401561 - 2¹ = 26401559 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (26401567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6766 + ... + 9928.

It is an arithmetic number, because the mean of its divisors is an integer number (3502548).

Almost surely, 2^26401561 is an apocalyptic number.

It is an amenable number.

26401561 is a deficient number, since it is larger than the sum of its proper divisors (1618823).

26401561 is a wasteful number, since it uses less digits than its factorization.

26401561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3671.

The product of its (nonzero) digits is 1440, while the sum is 25.

The square root of 26401561 is about 5138.2449338271. The cubic root of 26401561 is about 297.7669792263.

It can be divided in two parts, 26401 and 561, that added together give a palindrome (26962).

The spelling of 26401561 in words is "twenty-six million, four hundred one thousand, five hundred sixty-one".