20761913 has 4 divisors (see below), whose sum is σ = 21983220. Its totient is φ = 19540608.

The previous prime is 20761907. The next prime is 20761919. The reversal of 20761913 is 31916702.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31916702 = 2 ⋅15958351.

It is an interprime number because it is at equal distance from previous prime (20761907) and next prime (20761919).

It can be written as a sum of positive squares in 2 ways, for example, as 16908544 + 3853369 = 4112^2 + 1963^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20761913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20761919) 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, 610628 + ... + 610661.

It is an arithmetic number, because the mean of its divisors is an integer number (5495805).

Almost surely, 2^20761913 is an apocalyptic number.

It is an amenable number.

20761913 is a deficient number, since it is larger than the sum of its proper divisors (1221307).

20761913 is a wasteful number, since it uses less digits than its factorization.

20761913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1221306.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 20761913 is about 4556.5242235722. The cubic root of 20761913 is about 274.8458110851.

The spelling of 20761913 in words is "twenty million, seven hundred sixty-one thousand, nine hundred thirteen".