1631378857545 has 24 divisors (see below), whose sum is σ = 2830911385536. Its totient is φ = 869087791008.

The previous prime is 1631378857541. The next prime is 1631378857583. The reversal of 1631378857545 is 5457588731361.

1631378857545 is a `hidden beast` number, since 1 + 6 + 3 + 1 + 3 + 7 + 8 + 85 + 7 + 545 = 666.

It is not a de Polignac number, because 1631378857545 - 2² = 1631378857541 is a prime.

It is a super-2 number, since 2×1631378857545² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1631378857541) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20395747 + ... + 20475576.

It is an arithmetic number, because the mean of its divisors is an integer number (117954641064).

Almost surely, 2^{1631378857545} is an apocalyptic number.

1631378857545 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1631378857545 is a deficient number, since it is larger than the sum of its proper divisors (1199532527991).

1631378857545 is a wasteful number, since it uses less digits than its factorization.

1631378857545 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40872221 (or 40872218 counting only the distinct ones).

The product of its digits is 84672000, while the sum is 63.

The spelling of 1631378857545 in words is "one trillion, six hundred thirty-one billion, three hundred seventy-eight million, eight hundred fifty-seven thousand, five hundred forty-five".