30621981 has 16 divisors (see below), whose sum is σ = 46557504. Its totient is φ = 17735424.

The previous prime is 30621973. The next prime is 30622013. The reversal of 30621981 is 18912603.

It is not a de Polignac number, because 30621981 - 2³ = 30621973 is a prime.

It is a super-2 number, since 2×30621981² = 1875411440728722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (30621911) 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, 22431 + ... + 23756.

It is an arithmetic number, because the mean of its divisors is an integer number (2909844).

Almost surely, 2^30621981 is an apocalyptic number.

It is an amenable number.

30621981 is a deficient number, since it is larger than the sum of its proper divisors (15935523).

30621981 is a wasteful number, since it uses less digits than its factorization.

30621981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46220.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 30621981 is about 5533.7131295361. The cubic root of 30621981 is about 312.8559562040.

The spelling of 30621981 in words is "thirty million, six hundred twenty-one thousand, nine hundred eighty-one".