1231378605625 has 135 divisors (see below), whose sum is σ = 1906548300657. Its totient is φ = 792574272000.

The previous prime is 1231378605619. The next prime is 1231378605631. The reversal of 1231378605625 is 5265068731321.

It is a happy number.

The square root of 1231378605625 is 1109675.

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

It is an interprime number because it is at equal distance from previous prime (1231378605619) and next prime (1231378605631).

It can be written as a sum of positive squares in 22 ways, for example, as 1227621896361 + 3756709264 = 1107981^2 + 61292^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1231378605625 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (49).

It is an unprimeable number.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 3301282939 + ... + 3301283311.

Almost surely, 2^{1231378605625} is an apocalyptic number.

1231378605625 is the 1109675-th square number.

1231378605625 is the 554838-th centered octagonal number.

It is an amenable number.

1231378605625 is a deficient number, since it is larger than the sum of its proper divisors (675169695032).

1231378605625 is an frugal number, since it uses more digits than its factorization.

1231378605625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 814 (or 402 counting only the distinct ones).

The product of its (nonzero) digits is 1814400, while the sum is 49.

Multiplying 1231378605625 by its sum of digits (49), we get a square (60337551675625 = 7767725²).

1231378605625 divided by its sum of digits (49) gives a square (25130175625 = 158525²).

The spelling of 1231378605625 in words is "one trillion, two hundred thirty-one billion, three hundred seventy-eight million, six hundred five thousand, six hundred twenty-five".