1225549781 has 4 divisors (see below), whose sum is σ = 1231966464. Its totient is φ = 1219133100.

The previous prime is 1225549763. The next prime is 1225549789. The reversal of 1225549781 is 1879455221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1225549781 - 2²⁶ = 1158440917 is a prime.

It is a super-2 number, since 2×1225549781² = 3003944531418295922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1225549789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3208055 + ... + 3208436.

It is an arithmetic number, because the mean of its divisors is an integer number (307991616).

Almost surely, 2^1225549781 is an apocalyptic number.

It is an amenable number.

1225549781 is a deficient number, since it is larger than the sum of its proper divisors (6416683).

1225549781 is an equidigital number, since it uses as much as digits as its factorization.

1225549781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6416682.

The product of its digits is 201600, while the sum is 44.

The square root of 1225549781 is about 35007.8531332614. The cubic root of 1225549781 is about 1070.1475270427.

The spelling of 1225549781 in words is "one billion, two hundred twenty-five million, five hundred forty-nine thousand, seven hundred eighty-one".