25211405961 has 27 divisors (see below), whose sum is σ = 42367625703. Its totient is φ = 14404612320.

The previous prime is 25211405953. The next prime is 25211406007. The reversal of 25211405961 is 16950411252.

The square root of 25211405961 is 158781.

It is a perfect power (a square), and thus also a powerful number.

25211405961 is a `hidden beast` number, since 2 + 5 + 21 + 1 + 40 + 596 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6001445961 + 19209960000 = 77469^2 + 138600^2 .

It is not a de Polignac number, because 25211405961 - 2³ = 25211405953 is a prime.

It is a super-2 number, since 2×25211405961² (a number of 22 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (25211405911) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3330621 + ... + 3338181.

Almost surely, 2^25211405961 is an apocalyptic number.

25211405961 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

25211405961 is the 158781-st square number.

25211405961 is the 79391-st centered octagonal number.

It is an amenable number.

25211405961 is a deficient number, since it is larger than the sum of its proper divisors (17156219742).

25211405961 is an frugal number, since it uses more digits than its factorization.

25211405961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15142 (or 7571 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 36.

Multiplying 25211405961 by its sum of digits (36), we get a square (907610614596 = 952686²).

The spelling of 25211405961 in words is "twenty-five billion, two hundred eleven million, four hundred five thousand, nine hundred sixty-one".