21211020987 has 16 divisors (see below), whose sum is σ = 30741500160. Its totient is φ = 12930943392.

The previous prime is 21211020977. The next prime is 21211021003. The reversal of 21211020987 is 78902011212.

It is not a de Polignac number, because 21211020987 - 2⁸ = 21211020731 is a prime.

It is a super-2 number, since 2×21211020987² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21211020907) 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, 2537287 + ... + 2545632.

It is an arithmetic number, because the mean of its divisors is an integer number (1921343760).

Almost surely, 2^21211020987 is an apocalyptic number.

21211020987 is a deficient number, since it is larger than the sum of its proper divisors (9530479173).

21211020987 is a wasteful number, since it uses less digits than its factorization.

21211020987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5083042.

The product of its (nonzero) digits is 4032, while the sum is 33.

The spelling of 21211020987 in words is "twenty-one billion, two hundred eleven million, twenty thousand, nine hundred eighty-seven".