1553401649 has 4 divisors (see below), whose sum is σ = 1553500260. Its totient is φ = 1553303040.

The previous prime is 1553401637. The next prime is 1553401651. The reversal of 1553401649 is 9461043551.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9461043551 = 877 ⋅10787963.

It can be written as a sum of positive squares in 2 ways, for example, as 1520454049 + 32947600 = 38993^2 + 5740^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1553401649 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1553401679) 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, 19784 + ... + 59145.

It is an arithmetic number, because the mean of its divisors is an integer number (388375065).

Almost surely, 2^1553401649 is an apocalyptic number.

It is an amenable number.

1553401649 is a deficient number, since it is larger than the sum of its proper divisors (98611).

1553401649 is an equidigital number, since it uses as much as digits as its factorization.

1553401649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98610.

The product of its (nonzero) digits is 64800, while the sum is 38.

The square root of 1553401649 is about 39413.2166791801. The cubic root of 1553401649 is about 1158.1405129461.

The spelling of 1553401649 in words is "one billion, five hundred fifty-three million, four hundred one thousand, six hundred forty-nine".