1239813213961 has 27 divisors (see below), whose sum is σ = 1462930311591. Its totient is φ = 1047658528224.

The previous prime is 1239813213949. The next prime is 1239813214019. The reversal of 1239813213961 is 1693123189321.

It is a happy number.

The square root of 1239813213961 is 1113469.

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

It can be written as a sum of positive squares in only one way, i.e., 703778377225 + 536034836736 = 838915^2 + 732144^2 .

It is not a de Polignac number, because 1239813213961 - 2³³ = 1231223279369 is a prime.

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

It is not an unprimeable number, because it can be changed into a prime (1239813213911) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 568981570 + ... + 568983748.

It is an arithmetic number, because the mean of its divisors is an integer number (54182604133).

Almost surely, 2^{1239813213961} is an apocalyptic number.

1239813213961 is the 1113469-th square number.

1239813213961 is the 556735-th centered octagonal number.

It is an amenable number.

1239813213961 is a deficient number, since it is larger than the sum of its proper divisors (223117097630).

1239813213961 is an frugal number, since it uses more digits than its factorization.

1239813213961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4518 (or 2259 counting only the distinct ones).

The product of its digits is 419904, while the sum is 49.

Multiplying 1239813213961 by its sum of digits (49), we get a square (60750847484089 = 7794283²).

1239813213961 divided by its sum of digits (49) gives a square (25302310489 = 159067²).

The spelling of 1239813213961 in words is "one trillion, two hundred thirty-nine billion, eight hundred thirteen million, two hundred thirteen thousand, nine hundred sixty-one".