21497842761 has 16 divisors (see below), whose sum is σ = 28871289216. Its totient is φ = 14228519936.

The previous prime is 21497842759. The next prime is 21497842763. The reversal of 21497842761 is 16724879412.

It is an interprime number because it is at equal distance from previous prime (21497842759) and next prime (21497842763).

It is a cyclic number.

It is not a de Polignac number, because 21497842761 - 2¹ = 21497842759 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21497842763) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 184681 + ... + 277673.

It is an arithmetic number, because the mean of its divisors is an integer number (1804455576).

Almost surely, 2^21497842761 is an apocalyptic number.

It is an amenable number.

21497842761 is a deficient number, since it is larger than the sum of its proper divisors (7373446455).

21497842761 is a wasteful number, since it uses less digits than its factorization.

21497842761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93552.

The product of its digits is 1354752, while the sum is 51.

The spelling of 21497842761 in words is "twenty-one billion, four hundred ninety-seven million, eight hundred forty-two thousand, seven hundred sixty-one".