19961357 has 4 divisors (see below), whose sum is σ = 21496860. Its totient is φ = 18425856.

The previous prime is 19961351. The next prime is 19961363. The reversal of 19961357 is 75316991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75316991 = 991 ⋅76001.

It is an interprime number because it is at equal distance from previous prime (19961351) and next prime (19961363).

It can be written as a sum of positive squares in 2 ways, for example, as 10407076 + 9554281 = 3226^2 + 3091^2 .

It is a cyclic number.

It is not a de Polignac number, because 19961357 - 2⁸ = 19961101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19961351) 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, 767732 + ... + 767757.

It is an arithmetic number, because the mean of its divisors is an integer number (5374215).

Almost surely, 2^19961357 is an apocalyptic number.

It is an amenable number.

19961357 is a deficient number, since it is larger than the sum of its proper divisors (1535503).

19961357 is a wasteful number, since it uses less digits than its factorization.

19961357 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535502.

The product of its digits is 51030, while the sum is 41.

The square root of 19961357 is about 4467.8134473140. The cubic root of 19961357 is about 271.2668268777.

The spelling of 19961357 in words is "nineteen million, nine hundred sixty-one thousand, three hundred fifty-seven".