1225401661 has 8 divisors (see below), whose sum is σ = 1343589984. Its totient is φ = 1108344720.

The previous prime is 1225401649. The next prime is 1225401673. The reversal of 1225401661 is 1661045221.

It is an interprime number because it is at equal distance from previous prime (1225401649) and next prime (1225401673).

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

It is a cyclic number.

It is not a de Polignac number, because 1225401661 - 2⁵ = 1225401629 is a prime.

It is a super-3 number, since 3×1225401661³ (a number of 28 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225407661) 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, 280575 + ... + 284908.

It is an arithmetic number, because the mean of its divisors is an integer number (167948748).

Almost surely, 2^1225401661 is an apocalyptic number.

1225401661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1225401661 is a deficient number, since it is larger than the sum of its proper divisors (118188323).

1225401661 is a wasteful number, since it uses less digits than its factorization.

1225401661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 565691.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 1225401661 is about 35005.7375440084. The cubic root of 1225401661 is about 1070.1044126135.

Adding to 1225401661 its reverse (1661045221), we get a palindrome (2886446882).

The spelling of 1225401661 in words is "one billion, two hundred twenty-five million, four hundred one thousand, six hundred sixty-one".